Category Archives: News

WEATHER OUTLOOK (31 January – 15 February 2020)

1          For the first fortnight of February 2020, the Meteorological Service Singapore (MSS) forecasts warm and occasionally windy conditions on most days. Afternoon thundery showers are also expected later in the fortnight. The prevailing Northeast Monsoon season will continue, with low-level winds blowing from the northwest or northeast.

2          In the first half of the fortnight, the monsoon rain band is forecast to be located south of the Equator, and rain cloud formation over Singapore and the surrounding vicinity is likely to be suppressed. This is expected to bring warm and occasionally windy conditions on most days during the period. With the migration of the monsoon rain band closer to the Equator in the latter half of the fortnight, enhanced thunderstorm cloud development can be expected over Singapore. This is forecast to bring short-duration moderate to heavy thundery showers mostly in the afternoon on some days. The showers on most of these days are expected over parts of the island, and could be widespread on one or two days. Overall, rainfall for the first fortnight of February 2020 is forecast to be below normal over most parts of Singapore.

3         With warm conditions forecast in the first fortnight of February 2020, the daily temperature on most days is expected to range between 24°C and 34°C.

4         For updates of the daily weather and haze situation, please visit the MSS website (https://www.weather.gov.sg), NEA website (www.nea.gov.sg), or download the myENV app, MSS’ Weather@SG app, and the haze microsite (www.haze.gov.sg).

REVIEW (1 – 30 January 2020)

5          Northeast Monsoon conditions prevailed over Singapore and the surrounding region in January 2020. On most days during the month, the low-level winds blew from the north or northeast.

6          It was relatively windy on most days in January 2020, particularly during the first two weeks of the month. In the second half of January 2020, a weakening of the prevailing winds and the migration of the monsoon rain band closer to the equatorial Southeast Asia region brought more rainfall to Singapore and the surrounding vicinity. On some days in the second half of the month, strong daytime heating of land areas coupled with convergence of winds in the surrounding vicinity brought moderate to heavy thundery showers to Singapore in the afternoon. The intense thundery showers on 29 January 2020 recorded a daily total rainfall of 185.2mm at Jurong Island. This was the highest daily total rainfall recorded for January 2020 (as at 30 January 2020).

7          The second fortnight of January 2020 was generally warmer compared to the first fortnight of the month. The daily maximum temperature was between 31.6°C and 33.5°C in the first half of January 2020, and ranged between 32.0°C and 35.4°C on all days in the second half of the month except on 21 January 2020. On 21 January, the daily maximum temperature only reached 28.6°C due to several spells of widespread thundery showers that fell over the island between midnight and 3pm. The highest daily maximum temperature of 35.4°C was recorded at Newton on 26 January 2020. At the climate station in Changi, the mean monthly temperature for January 2020 of 27.7°C (as of 30 January 2020) was 1.2°C higher than the long-term average. January 2020 is on track to be the fourth warmest January since temperature records began in 1929.

8          Most parts of the island recorded below-average rainfall in January 2020. The highest anomaly of 61% below average was recorded at Changi. The rainfall recorded over the southwestern part of Singapore around Jurong was 16% above-average.

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CLIMATE STATION STATISTICS

Long-term Statistics for February
(Climatological reference period: 1981 – 2010)

Historical Extremes for February
(Rainfall since 1869 and temperature since 1929)

WEATHER OUTLOOK (31 December 2019 – 15 January 2020)

Singapore, 31 December 2019 – The prevailing wet phase of the Northeast Monsoon season in the region is forecast to continue into January 2020. The low-level winds during the first two weeks of the year are expected to blow from the northwest or northeast.

2        From the eve of the New Year, the northeasterly winds over the South China Sea, including Singapore are forecast to strengthen and persist before weakening around the end of the week. This is expected to bring windy conditions throughout the week, including on New Year’s Day. Toward the end of the week, periods of light to moderate showers are expected on a few days. In the second week of January 2020, convergence of winds coupled with strong daytime heating of land areas is likely to bring short-duration moderate to heavy thundery showers, mostly in the afternoon on 3 to 4 days. In addition, the presence of a low-pressure system over the South China Sea could bring widespread thundery showers accompanied by gusty winds to Singapore between the predawn and morning on one or two days. Overall, the rainfall for the first two weeks of January 2020 is likely to be below-normal over most parts of Singapore.

3         In the first fortnight of January 2020, the daily temperatures on most days are forecast to range between 24°C and 33°C, and could dip to a low of around 23°C on a few nights. The daily maximum temperature could still reach a high of around 34°C on a few days.

4         For updates of the daily weather and haze situation, please visit the MSS website (https://www.weather.gov.sg), NEA website (www.nea.gov.sg), or download the myENV app, MSS’ Weather@SG app, and the haze microsite (www.haze.gov.sg).

REVIEW (1 – 30 December 2019)

5        Northeast Monsoon conditions persisted over Singapore in December 2019, with low-level winds blowing mainly from the north or northeast.

6         December 2019 was a relatively wet month. Strong solar heating of land areas coupled with convergence of winds in the surrounding region brought moderate to heavy thundery showers in the afternoon on the first few days of the month. The intense thundery showers on 2 December 2019 recorded a daily total rainfall of 102.8mm at Bukit Panjang. This was the highest daily total rainfall recorded for December 2019 (as of 30 December 2019).

7          A surge of northeast monsoon winds prevailed over the equatorial South China Sea region in the first half of the month. Between 5 and 15 December 2019, the surge brought cloudy and windy conditions to Singapore. During the period from 9 to 11 December 2019, periods of moderate to occasionally heavy rain showers fell over the island, and over the last three days (13 to 15 December 2019) of the fortnight, the rain showers were widespread and fell continuously before dissipating in the evening of 15 December 2019. The highest daily total rainfall recorded throughout this monsoon surge event was 100.4 mm on 9 December 2019 at Pulau Ubin. In the second half of December 2019, the thundery showers were of short-duration and fell mostly in the afternoon. The heaviest rainfall recorded during the period was 63.3 mm at Queenstown on 18 Dec 2019 (as of 30 Dec 2019).

8          The monsoon surge and the accompanying rainy weather in the first half of the month brought several cool days. From 8 to 15 December 2019, the daily maximum temperature ranged between 25.2°C and 29.9°C on all days except 12 December 2019. The lowest daily maximum temperature for December 2019 (as of 30 Dec 2019) was 25.2°C, recorded on 15 December 2019 at Changi. The daily minimum temperature dipped to 23°C and below on seven consecutive days (10 – 16 December 2019) at stations in the northern, central and eastern parts of the island. The lowest daily minimum temperature recorded in December 2019 (as of 30 December) was 21.4 °C, recorded on 2 December 2019 at Admiralty. The lowest–ever recorded daily minimum temperature for December is 20.6°C at Paya Lebar in 1964.

9          At the climate station in Changi, the monthly total rainfall of 421.5 mm for December 2019 (as of 30 Dec 2019) has outranked the December 2017 total rainfall record (371.2mm) as the wettest December in Singapore in the last 10 years. December 2019 was also the windiest December in the last 10 years with an average daily wind speed of 9.8 km/h (as of 30 Dec 2019). The last occurrence when the Changi climate station recorded an average daily wind speed stronger than 9.8 km/hr was in 2009 (at 11.9 km/h).

10        Most parts of the island recorded above-average rainfall in December 2019. The highest anomaly of 51% above average was recorded at Pasir Ris. The anomaly was lowest at Jurong at 18% below average.

CLIMATE STATION STATISTICS

Long-term Statistics for January
(Climatological reference period: 1981 – 2010)

Historical Extremes for January
(Rainfall since 1869 and temperature since 1929)

WEATHER OUTLOOK (16 – 31 December 2019)

Singapore, 16 December 2019 – Singapore and the surrounding region are currently in the wet phase of the Northeast Monsoon season. This phase is expected to prevail into January 2020 before transitioning to the dry phase of the season (February – mid-March). For the second fortnight of December 2019, the low-level winds are forecast to blow from the northwest or northeast.

2          For the rest of December 2019, strong daytime heating of land areas coupled with localised convergence of winds are expected to influence the weather in Singapore on eight to ten days in the fortnight. These conditions are conducive for localised thunderstorm cloud development, and are forecast to bring moderate to heavy thundery showers in the afternoon. On some of these days, the showers could extend into the evening. Showers are likely around the Christmas period. Overall, the rainfall for December 2019 is expected to be well above average.

3          In the last fortnight of 2019, the daily temperatures are forecast to range between 24°C and 33°C on most days, and could dip to a low of around 23°C on a few days.

4         For updates of the daily weather and haze situation, please visit the MSS website (https://www.weather.gov.sg), NEA website (www.nea.gov.sg), or download the myENV app, MSS’ Weather@SG app, and the haze microsite (www.haze.gov.sg).

REVIEW (1 – 15 December 2019)

5          Northeast Monsoon conditions prevailed over Singapore and the surrounding region in the first fortnight of December 2019.  During the period, it was windy with low-level winds blowing from the northeast or east, arising from the monsoon surge that prevailed on most days over the equatorial Southeast Asia region including Singapore.

6          On the first few days of December 2019, strong solar heating of land areas coupled with convergence of winds in the surrounding region brought moderate to heavy thundery showers in the afternoon. The intense thundery showers on 2 December 2019 recorded a daily total rainfall of 102.8mm at Bukit Panjang. This was the highest daily total rainfall recorded for the first fortnight of December 2019. A surge of northeast monsoon winds prevailed throughout the fortnight since 5 December 2019, and brought cloudy and windy conditions to Singapore. While there were some passing showers over the island in the first week, periods of moderate to occasionally heavy rain/showers fell on all but one day in the second week of December 2019. Over the 13 December 2019 weekend, the rain was widespread and fell continuously over the island before dissipating in the evening of 15 December 2019. The highest daily total rainfall recorded over this weekend was 80.9mm on 15 December 2019 at Loyang. The highest daily total rainfall recorded throughout this monsoon surge event was 100.4 mm on 9 December 2019 at Pulau Ubin.

7          Compared to the last fortnight of November 2019, the rainy weather in the first fortnight of December 2019 brought cooler temperatures across Singapore. The daily maximum temperature in the first week of the fortnight ranged between 27.3°C and 34.9°C but dipped to between 25.2°C and 32.3°C in the second week of the fortnight due to the rainy weather arising from the monsoon surge. The lowest daily maximum temperature of 25.2°C was recorded on 15 December 2019 at Changi. The lowest daily minimum temperature recorded in the fortnight was 21.4°C on 2 December 2019 at Admiralty, arising from the intense thunderstorm that fell over the island that afternoon.

8          In the first half of December 2019, Singapore recorded above-average rainfall across the island. Pasir Ris recorded the highest rainfall anomaly of 151% while Ulu Pandan recorded the lowest rainfall anomaly of 10% above average.

CLIMATE STATION STATISTICS

Long-term Statistics for December
(Climatological reference period: 1981 – 2010)

Historical Extremes for December
(Rainfall since 1869 and temperature since 1929)

WEATHER OUTLOOK (30 November – 15 December 2019)

1        Singapore has been experiencing Northeast Monsoon conditions since early November 2019, and these conditions are expected to last until March 2020. During this period, the prevailing winds are forecast to blow from the north or northeast.

2          The Northeast Monsoon season has two phases, a wet phase typically between December and January and a dry phase, usually between February and March. During the first phase of the season, the monsoon rain band lies over the equatorial South China Sea, and usually brings increased cloudiness and rain showers over Singapore and the surrounding region. In addition, on occasions when there is an intensification of a high-pressure system over the northern Asian continent, this could bring a surge or strengthening of northeast winds over the South China Sea, blowing toward the equatorial Southeast Asia region. Singapore and the surrounding region can expect a few such monsoon surges[1] during the wet phase of the season, and the surge can bring several days of widespread continuous rain/showers over southern Johor and Singapore.

3          In the first week of December 2019, the southern South China Sea region including Singapore can expect a monsoon surge lasting from two to four days. The surge is likely to bring cloudy and occasionally windy conditions with periods of widespread moderate to heavy showers over Singapore. The strong northeasterly winds over the South China Sea are forecast to weaken in the second week of December 2019. For the rest of the fortnight, Singapore can expect short-duration moderate to heavy thundery showers in the afternoon on five to seven days. This is due to strong solar heating of land areas coupled with localised convergence of winds. Overall, most parts of Singapore can expect above-normal rainfall in the first fortnight of December 2019.

4          The monsoon surge event in the first week December 2019 is also expected to bring cooler daily temperatures of between 22°C and 30°C.  For the rest of the fortnight, the daily temperatures are forecast to range between 24°C and 33°C, and could dip to a low of 23°C on a few nights. The daily maximum temperature could still reach a high of around 34°C on a few days.

5         For updates of the daily weather and haze situation, please visit the MSS website (https://www.weather.gov.sg), NEA website (www.nea.gov.sg), or download the myENV app, MSS’ Weather@SG app, and the haze microsite (www.haze.gov.sg).

REVIEW (1 – 29 November 2019)

5          In November 2019, the inter-monsoon conditions transitioned to the Northeast Monsoon conditions as the low-level winds which were light and variable in direction, strengthened to blow from the northwest or northeast.

6          During the month, strong solar heating of land areas coupled with localised convergence of winds led to the development of short-duration thundery showers over Singapore. The showers fell mostly in the afternoon, and on some days, extended into the evening. The thundery showers at Loyang (as at 5:31 pm) on 29 November 2019 recorded a daily total rainfall of 102.5 mm. This is the highest daily total rainfall recorded for November 2019. On that day, thundery showers fell over many parts of the island in the afternoon due to a convergence of winds over the surrounding region.

7          Although it rained across the island on most days of the month, more than half the month still recorded daily maximum temperatures of above 34°C. On 7 November 2019, the highest daily maximum temperature recorded at all stations across the island was 35.0°C at Paya Lebar on 10 Nov 2019.

8          At the climate station in Changi, the highest daily maximum temperature recorded in November 2019 (as of 28 November 2019) was 34.4°C on 17 November 2019. Based on long-term climate station records, this is 0.2°C higher than the highest ever-recorded daily maximum temperature in November on 26 November 2000. November 2019 is also likely to be on track to be the warmest  November since temperature records began in 1929, with mean temperature of 28.1°C (as of 28 November 2019). This is 0.1°C above the highest record of 28.0°C in November 1998 and 2015.

9          In November 2019, many parts of Singapore recorded below-average rainfall. Sentosa recorded the highest rainfall anomaly of 79% below average while Choa Chu Kang recorded the highest rainfall anomaly of 18% above average.

[1] A monsoon surge refers to the strengthening of northeasterly winds blowing from a strong high-pressure system over the northern Asian continent toward the South China Sea, bringing periods of prolonged widespread rain and windy conditions to the surrounding region including Singapore and Peninsular Malaysia. (Further information is available at  https://www.weather.gov.sg/learn_weather_systems/)

CLIMATE STATION STATISTICS

Long-term Statistics for December
(Climatological reference period: 1981 – 2010)

Historical Extremes for December
(Rainfall since 1869 and temperature since 1929)

Singapore, 15 November 2019 – In the second half of November 2019, the prevailing inter-monsoon conditions are expected to transition to the Northeast Monsoon. During this period, the prevailing low-level winds that are light and variable in direction are forecast to gradually strengthen and blow from the northeast or northwest. The Northeast Monsoon season, which is also the rainy season over southern Southeast Asia, is expected to extend into March 2020.

2          During the Northeast Monsoon season, the low-level winds originating from East Asia gather moisture as they pass over the South China Sea and converge over the equatorial Southeast Asia region. This enhances the development of the monsoon rain band lying over the region, and brings more showers to Singapore and the surrounding region. As a result, coupled with strong solar heating of land areas during the day, Singapore can expect short-duration thundery showers in the afternoon on seven to nine days in the second half of November 2019.

3          Around the end of the month, a further strengthening of the northeasterly winds over the equatorial South China Sea is expected. This is likely to bring cloudy conditions and moderate to heavy thundery showers over Singapore between the late morning and evening on one or two days. Overall, the rainfall for November 2019 is likely to be near-normal for most parts of Singapore.

4          With more rain days forecast in the last two weeks of November 2019, it is expected to be slightly cooler compared to the warm days experienced over the past weeks. The daily temperature on most days is forecast to range between 24°C and 33°C. There could still be one or two warm days where the daily maximum temperature could reach a high of around 34°C. On a few nights, the daily minimum temperature could reach a low of around 23°C.

5          For the rest of November 2019, the gradual strengthening of the northeasterly winds over the equatorial Southeast Asia region is expected to alleviate any occasional slight haziness due to the accumulation of particulate matter in the atmosphere under light wind conditions.

6         For updates of the daily weather and haze situation, please visit the MSS website (https://www.weather.gov.sg), NEA website (www.nea.gov.sg), or download the myENV app, MSS’ Weather@SG app, and the haze microsite (www.haze.gov.sg).

REVIEW (1 – 15 November 2019)

7          In the first fortnight of November 2019, Singapore and the surrounding region experienced inter-monsoon conditions with low-level winds that were generally light and variable in direction.

8          In the fortnight, short-duration thundery showers fell over parts of the island between the late morning and afternoon on all but two days during the period. Compared to the last fortnight of October 2019, the showers in the first fortnight of November 2019 were less widespread and less intense. This was due to the slight northward shift of the monsoon rain band away from the Equator because of the development of low-pressure systems in the northern South China Sea and Pacific Ocean. On 5 November 2019, thundery showers fell over many parts of the island in the late morning and early afternoon due to convergence of winds feeding into rain bands extending from Typhoon Nakri in the South China Sea. The highest daily total rainfall recorded that day was 47.4mm over the southern part of the island at Kent Ridge.

9          Singapore recorded slightly warmer temperatures in the first fortnight of November 2019 compared to the last fortnight of October 2019. The daily maximum temperatures reached above 34°C for more than half of the fortnight, and the highest daily maximum temperature recorded was 34.9°C on 7 November 2019 at Marina Barrage and Ang Mo Kio.

10        On a few days toward the end of the fortnight, Singapore experienced slight haziness with the 24-hr PSI ranging between the high end of the Moderate and the low end of the Unhealthy range. The slight haziness was due to the accumulation of particulate matter in the atmosphere under light wind conditions. While some showers on 12 and 13 November 2019 helped to improve the air quality over the island, the light winds slowed the dispersion of the particles and the haziness lingered over the two days. The air quality improved to the Moderate range on 14 November 2019. This was due to the occurrence of showers over the island and surrounding vicinity and a strengthening and shift of winds to blow from the northeast over Singapore from the early hours of 14 November 2019.

11        In the first half of November 2019, most parts of Singapore recorded below-average rainfall. Sentosa recorded the highest rainfall anomaly of 96% below average while Ang Mo Kio recorded the highest rainfall anomaly of 14% above average.

CLIMATE STATION STATISTICS

Long-term Statistics for November
(Climatological reference period: 1981 – 2010)

Historical Extremes for November
(Rainfall since 1869 and temperature since 1929)

Singapore, 16 October 2019 – Singapore has been experiencing inter-monsoon conditions since early October 2019. These conditions are forecast to prevail for the rest of October and extend into November 2019.  The inter-monsoon period is characterised by thundery showers and low level winds that are light and variable in direction.

2          For the rest of October 2019, the low level winds are expected to be mostly light and variable in direction, and may strengthen and shift to blow from the southeast on a few days. This temporary change in winds can be partly attributed to the strengthening of a high pressure system over the southern Indian Ocean.

3          During the fortnight, the equatorial Southeast Asia region, including Singapore, can expect more showers in the first week of the fortnight. This is due to the presence of the monsoon rain band over the equatorial region coupled with convergence on winds in the surrounding vicinity. For Singapore, short-duration moderate to heavy thundery showers are forecast in the afternoon on eight to ten days. The thundery showers can extend into the evening on a few of these days, and can be accompanied by frequent lightning activity. Overall, the rainfall for Singapore in October 2019 is expected to be near-normal.

4         For the rest of the month, with the expected increase in rainfall over the region, the likelihood of transboundary haze affecting Singapore is low. However, Singapore could experience slightly hazy conditions on a few days, particularly in the early morning due to an accumulation of particulate matter in the atmosphere under light and variable wind conditions.

5          ​The warm conditions experienced in the first fortnight of October 2019 are forecast to continue for the rest of October 2019, with the daily maximum temperature reaching a high of 35°C on a few days. On most days, the daily temperature is forecast to range between 25°C and 34°C.

6         For updates of the daily weather and haze situation, please visit the MSS website (https://www.weather.gov.sg), NEA website (www.nea.gov.sg), or download the myENV app, MSS’ Weather@SG app, and the haze microsite (www.haze.gov.sg).

REVIEW (1 – 15 October 2019)

7        Southwest Monsoon conditions transitioned to inter-monsoon conditions in the first half of October 2018. The presence of the monsoon rain band located near the equatorial region brought more showers over Singapore and the surrounding region. This brought some relief to the dry weather conditions experienced in Singapore in recent months.

8          During the first fortnight of October 2019, short-duration thundery showers fell over the island mostly in the afternoon due to the light winds coupled with strong solar heating of land areas. On 7 October 2019, strong wind convergence over the equatorial Southeast Asia region brought widespread thundery showers over Singapore between late morning and evening. On that day, the daily total rainfall of 76mm recorded at Pasir Ris was the highest recorded daily total rainfall in the first half of October 2019.

9          Despite the increased showers, there were still some warm days with the daily maximum temperature exceeding 34°C. The highest daily maximum temperature of 35.7°C was recorded at Clementi on 13 October 2019.

10          Below-average rainfall was recorded across Singapore in the first half of October 2019. Sentosa recorded the highest anomaly of 92% below-average.

CLIMATE STATION STATISTICS

Long-term Statistics for October
(Climatological reference period: 1981 – 2010)

Historical Extremes for October
(Rainfall since 1869 and temperature since 1929)

New temperature and rainfall records for September 2019

Singapore, 1 October 2019 – In the first fortnight of October 2019, the prevailing Southwest Monsoon conditions with low level winds blowing from the southeast or south are forecast to gradually weaken to become light and variable in direction. This change in conditions signal the cessation of the Southwest Monsoon season and the start of the inter-monsoon period.

2          Inter-monsoon conditions are forecast to prevail through November 2019, and is characterised by light winds and thunderstorms that are intense at times. The light winds, high moisture and strong day time heating of land areas are conducive for thunderstorm development. Lightning activity tends to be higher during the inter-monsoon period compared to other times of the year.

3          The monsoon rain band that has been hovering over the equatorial Southeast Asia region since late September 2019 is forecast to maintain its position over the region in the coming fortnight. This is expected to bring short-duration thundery showers over Singapore, mostly in the afternoon on eight to ten days. On a few of these days, the thundery showers can be expected in the late morning and extend into the afternoon. The rainfall for the first fortnight of October 2019 is forecast to be slightly above-normal over most parts of Singapore.

4          In the coming fortnight, more showers are forecast for the southern Southeast Asia region. The increase in rainfall is expected to bring a further improvement to the haze situation in the region, and the likelihood of transboundary haze affecting Singapore is thus low. However, Singapore could experience slightly hazy conditions on a few days, particularly in the early morning, due to an accumulation of particulate matter in the atmosphere under light wind conditions.

5          The first half of October 2019 is also forecast to be warm with the daily maximum temperature exceeding 35°C on a few days. On most days, the daily temperature is forecast to range between 25°C and 34°C. The night-time temperatures in the southern and eastern coastal areas of the island are expected to be warmer with daily minimum temperatures of 27°C or more on some days.

6         For updates of the daily weather and haze situation, please visit the MSS website (https://www.weather.gov.sg), NEA website (www.nea.gov.sg), or download the myENV app, MSS’ Weather@SG app, and the haze microsite (www.haze.gov.sg).

REVIEW (1 – 30 September 2019)

7         In September 2019, Southwest Monsoon conditions prevailed over the region with the low level winds blowing from the southeast or south, and on occasions from the southwest.

8          Singapore experienced drier and warmer-than-normal conditions in the first three weeks of September 2019. These conditions were due to suppressed raincloud formation arising from dry air blown to the southern Southeast Asia region from high pressure systems over Australia, coupled with the persisting cooler sea surface temperatures over the tropical Indian Ocean. There were however a few days during this period when showers fell over Singapore. In particular, the thundery showers on 4 September 2019 due to convergence of winds over Singapore and the surrounding vicinity brought showers over many parts of the island. The highest daily total rainfall of 93.3mm recorded over Jurong West that day was the highest recorded for September 2019.

9          In contrast, the last week of September 2019 was wet. The rainy weather was due to the moisture-laden easterly winds that were blown to the southern Southeast Asia region from the tropical Pacific Ocean. On 27 September 2019, an intense thunderstorm over the Tuas area generated a rotating column of winds, known as a landspout, over Gul Way. The landspout, which is the first reported occurrence in Singapore, lasted for several minutes and ripped off parts of a building’s roof.

10          Between 9 and 23 September 2019, Singapore experienced hazy conditions due to smoke haze from land and vegetation fires in Sumatra blown in by the prevailing winds. The 24-hour PSI during this period was between the Moderate and Unhealthy range, and remained in the Unhealthy range on some days (14-15 Sep, 17-19 Sep and 21 – 23 Sep 2019). The highest 24-hour PSI reading of 154, in the mid-section of the Unhealthy range, was recorded in southern Singapore between 2am and 4am on 19 September 2019. Showers in the last week of September 2019 helped to ease the hazy conditions over Singapore.

11        September 2019 was warm with the highest daily maximum temperature across the island reaching at least 34°C on more than 15 days in the month. The highest daily maximum temperature of 35.0°C was recorded at Tai Seng on 21 September 2019.

12        Based on the climate station records, September 2019 is the warmest and the driest September in Singapore since temperature and rainfall records began in 1929 and 1869 respectively. The monthly mean temperature for September 2019 was 29.0^oC, 0.2^oC warmer than the previous record set in September 1997. September 2019 also saw a new record for the highest September mean daily maximum of 33.0^oC, far exceeding the previous record of 32.2^oC (in September 1997) by 0.8^oC. Another record was set for the highest September mean daily minimum temperature of 26.6^oC, 0.1^oC higher than the previous record in September 2015. The monthly total rainfall last month was 22.8 mm, breaking the previous September record low rainfall of 23.7 mm in September 1994.

13       Significantly below-average rainfall was recorded across Singapore in September 2019. The lowest anomaly of 85% or more below-average was recorded at a few stations in the eastern part of the island. The total rainfall recorded at rainfall stations across the island with long-term records for September 2019 was 44% below September’s climatological normal.  September 2019 is thus the third consecutive month, following July and August 2019, with more than 40% below-normal monthly rainfall giving rise to a rainfall deficit situation[1] (the total rainfall for July 2019 and August 2019 was 51% and 81% below normal respectively). The last occurrence of a rainfall deficit situation in Singapore was in 2014 from January to March, where the average rainfall total for each month across Singapore was 67%, 89% and 50% below the month’s normal.

[1] A rainfall deficit situation refers to a period of at least 3 consecutive months with monthly rainfall more than 40% below the climatological rainfall, averaged over the rainfall stations with long term records across the island. 

CLIMATE STATION STATISTICS

Long-term Statistics for October
(Climatological reference period: 1981 – 2010)

Historical Extremes for October
(Rainfall since 1869 and temperature since 1929)