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Singapore, 16 September 2019 – The prevailing Southwest Monsoon conditions in the region are forecast to persist for the rest of September 2019. During this period, the low level winds are expected to blow from the southeast or south, and on occasions, shift to blow from the southwest.

2          In the coming fortnight, dry air from high pressure systems over northern Australia are forecast to continue blowing over the southern Southeast Asia region, including Singapore. Persisting cooler sea surface temperatures  over the tropical eastern Indian Ocean[1] (positive Indian Ocean Dipole) will also suppress raincloud formation over the surrounding region. Additionally, with the monsoon rain band forecast to remain over northern Southeast Asia, away from Singapore, the prevailing dry weather is expected to continue into the second fortnight of the month.

3          In the last week of the month, there could be some brief respite as the high pressure system over northern Australia is expected to weaken, and with strong solar daytime heating of land areas, localised short-duration showers can be expected in the afternoon on a few days.

4          The rainfall for September 2019 is likely to be significantly below September’s climatological normal of 185.4mm.  September 2019 is thus likely to be the third consecutive month, following July and August 2019, with more than 40% below-normal monthly rainfall, giving rise to a potential rainfall deficit [2] situation. The total rainfall for July and August 2019 recorded at rainfall stations across the island with long term records was 51% and 82% 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.

5          For the rest of September 2019, the prevailing warm conditions are forecast to continue. The daily temperature is expected to range between 26°C and 34°C on most days, with highs exceeding 35°C on a few days. The nights are expected to be warm with daily minimum temperatures of 27°C or more on some days. Night-time temperatures in the southern and eastern coastal areas could be warmer, at around 28°C, when prevailing winds blowing from the southeast bring warm and humid air from the surrounding seas.

6          The prevailing dry weather over southern Southeast Asia is expected to persist in the coming fortnight. Hotspots with smoke plumes continue to be observed over parts of Sumatra and Kalimantan. Singapore may continue to experience hazy conditions during the fortnight, depending on the wind conditions and the proximity and extent of the fires.

7         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 September 2019)

8          During the first fortnight of September 2019, Southwest Monsoon conditions continued to prevail, and the low level winds blew from the southeast or southwest.

9          In the first half of September 2019, the weather over Singapore was generally dry and warm. These conditions were due to suppressed raincloud formation arising from dry air that was blown to the southern Southeast Asia region from high pressure systems over northern Australia, coupled with the persisting cooler sea surface temperature over the tropical Indian Ocean. There were however a few days when brief showers fell over Singapore. In particular, on 4 September 2019, the thundery showers over many parts of the island were due to convergence of winds over Singapore and the surrounding vicinity. Rainfall was heaviest over the western part of the island, and the highest daily total rainfall recorded that day was 93.3mm at Jurong West.

10        In the second week of September 2019, smoke haze from hotspots in central and southern Sumatra were blown in by the prevailing winds to Singapore. This brought slightly hazy conditions to the island with the air quality in the high end of the Moderate range on most days of the week. A sudden deterioration in the haze situation on 14 September 2019 caused the 24-hour PSI to dip into the Unhealthy range.

11        The first half of September 2019 was warm, with daily maximum temperatures reaching at least 34.0°C on 9 days (as at 13 September 19). The highest daily maximum temperature of 34.8°C was recorded on 12 September 2019 over the northern part of the island at Admiralty.

12        Significantly well-below-average rainfall was recorded across the island in September 2019. The lowest anomaly of 100% below-average was recorded at a few stations in the eastern part of the island.

[1] The Indian Ocean Dipole (IOD) refers to the sustained change to the difference between sea surface temperatures (SSTs) of the tropical western and eastern Indian Ocean. The IOD varies between three phases – positive, negative and neutral. A positive (negative) phase occurs when cooler (warmer) SSTs develop in the eastern Indian Ocean, resulting in below (above) normal rainfall in the eastern Indian Ocean and the surrounding region. More information on the IOD can be found at https://www.weather.gov.sg/LEARN_climate/.

[2] A rainfall deficit 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 September
(Climatological reference period: 1981 – 2010)

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

August 2019 likely the driest and warmest August on record

Singapore, 30 August 2019 – The prevailing Southwest Monsoon conditions in the region are forecast to persist in the first fortnight of September 2019.  During the period, the low level winds are forecast to blow mostly from the southeast or southwest, and may on brief occasions, shift to blow from the west.

2          During the fortnight, the monsoon rain band is forecast to remain over the northern Southeast Asia region, away from Singapore. Under the influence of cooler sea surface temperatures over the tropical eastern Indian Ocean, dry weather is forecast to prevail over Singapore and the surrounding region in the first fortnight of September 2019. However, localised short-duration thundery showers can still be expected on four or five days between the late morning and early afternoon. In addition, Sumatra squalls are forecast to bring thundery showers and gusty winds on one or two mornings. The rainfall in the first fortnight of September is likely to be significantly below normal.

3          The first fortnight of September 2019 is expected to be as warm as the last month. On most days, the daily temperature is forecast to range between 26°C and 34°C, with highs of around 35°C on a few days. Warm nights with daily minimum temperatures above 26°C are expected on some days, reaching around 28°C in the southern and eastern coastal areas when prevailing winds blowing from the southeast bring in warm and humid air from the surrounding seas.

4          The weather in the surrounding region is also forecast to be dry in the coming weeks. Hotspots with smoke plumes continue to be observed in parts of Sumatra and Kalimantan. Depending on the direction of the prevailing winds and the proximity and extent of the fires, Singapore may experience occasional haze.

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 August 2019)

6          In August 2019, Southwest Monsoon conditions continued to persist with the low level winds blowing from the southeast or southwest.

7          The weather over Singapore and the surrounding region has been dry since late July 2019. Between 31 July and 16 August 2019, Singapore experienced a dry spell[1] of 17  consecutive days. The dry spell eased on 17 August 2019 when showers fell over many parts of the island that day. The highest rainfall recorded on 17 August 2019 was 13.0 mm around the city area. The extended dry weather can be attributed to an intrusion of dry air from high pressure systems over northern Australia coupled with suppressed raincloud formation due to cooler sea surface temperatures over the tropical eastern Indian Ocean (positive phase of Indian Ocean Dipole (IOD)[2]).

8          For the rest of August 2019, it was dry and warm on most days with a few days of thundery showers which brought some welcome relief from the hot and humid conditions. On 26 August 2019, strong solar heating of land areas coupled with large-scale wind convergence brought widespread moderate to heavy thundery showers over many parts of the island. The highest daily total rainfall recorded that day was 78.4 mm at Yishun. At the climate station in Changi, the total rainfall recorded for August 2019 was 11.8 mm (as of 29 August 2019), lower than the August record low rainfall of 18.0 mm in 1888. August 2019 is thus on track to be the driest August in Singapore since rainfall records began in 1869.

9          August 2019 was also a warm month, with daily maximum temperatures reaching at least 34°C on 13 days (as at 29 August 2019). The highest temperature of 34.8°C was recorded at Marina Barrage on 23 August 2019. The nights were generally warm with daily minimum temperatures above 26°C recorded over most parts of Singapore. There were a few nights in the southern and eastern coastal areas of the island where the minimum temperature was around 28°C.

10        At the climate station in Changi, the mean monthly temperature for the month is 29.1°C (as at 29 August 2019). This is 0.2°C above the highest ever mean monthly temperature for August, recorded in 2016. August 2019 is thus likely to be the warmest ever August in Singapore since temperature records started in 1929. For the month to date, the average minimum temperature for August 2019 was 27.1°C, 0.9°C above the August record high temperature of 26.2°C in 2016.

11        Significantly well-below-average rainfall was recorded across the island in August 2019. The lowest anomaly of 98% below-average was recorded at Paya Lebar.

[1] A dry spell is defined as a period of at least 15 consecutive days with daily total rainfall of less than 1.0 mm, averaged over rainfall stations with long-term records across the island.

[2] The Indian Ocean Dipole (IOD) refers to the sustained change to the difference between sea surface temperatures (SSTs) of the tropical western and eastern Indian Ocean. The IOD varies between three phases – positive, negative and neutral. A positive (negative) phase occurs when cooler (warmer) SSTs develop in the eastern Indian Ocean, resulting in below (above) normal rainfall in the eastern Indian Ocean and the surrounding region. More information on the IOD can be found at https://www.weather.gov.sg/LEARN_climate/.

CLIMATE STATION STATISTICS

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

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

Singapore, 16 August 2019 – The prevailing Southwest Monsoon conditions are forecast to persist over Singapore and the surrounding region for the rest of August 2019, and extend into October 2019. During this period, the prevailing winds are forecast to blow mostly from the southeast or southwest.

2          In the second fortnight of August 2019, dry conditions are forecast on most days as dry air from high pressure systems over northern Australia extends to the equatorial region. Singapore has been experiencing a dry spell [1] since 31 July 2019. With thundery showers expected in the late morning and early afternoon on four or five days toward the last week of August 2019, the showers will bring some respite to the current dry spell. On some days, breezy conditions can be expected due to the occasional strengthening of winds over the equatorial region. Rainfall for the month is expected to be significantly below normal.

3         The rest of August 2019 is expected to be warm. On most days, the daily temperature is forecast to range between 26°C and 34°C, with highs of around 35°C on a few days. The minimum temperature on some nights can hover around 28°C, when prevailing winds blowing from the southeast bring in warm and humid air from the surrounding seas.

4         The dry weather in the surrounding region is forecast to persist. Hotspots with smoke plumes continue to be observed in various parts of Sumatra and Kalimantan. Depending on the direction of the prevailing winds and location of the fires, Singapore may experience occasional haze.

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

REVIEW (1 – 15 August 2019)

6          During the first fortnight of August 2019, Southwest Monsoon conditions prevailed with the low level winds blowing from the southeast or southwest.

7          The dry weather prevailing in Singapore and the surrounding region since late July 2019 persisted in the first half of August 2019. Singapore experienced a dry spell [1] of 16  consecutive days between 31 July and 15 August 2019. While brief localised showers fell on some days, most parts of Singapore were dry with about 90% of all stations island-wide recording daily rainfall below 0.2 mm. The last recorded dry spell in Singapore lasted 27 days from 17 February to 15 March 2014. The extended dry weather can be attributed to an intrusion of dry air from northern Australia coupled with suppressed raincloud formation due to cooler sea surface temperatures over the tropical eastern Indian Ocean (positive phase of Indian Ocean Dipole (IOD)[2]).

8          The dry weather also contributed to a very warm first half of August 2019, with the daily maximum temperature ranging between 31.9°C and 34.5°C. The highest temperature of 34.5°C was recorded at Marina Barrage on 13 August 2019. The nights were generally warm with daily minimum temperatures above 26°C recorded over most parts of Singapore. There were a few nights where the temperature remained around 28°C in the southern and eastern coastal areas of Singapore.

9          In the first fortnight of August 2019, significantly below-average rainfall was recorded at all stations across the island. The rainfall anomaly was close to 100% below-average for many parts of Singapore.

[1] A dry spell is defined as a period of at least 15 consecutive days with daily total rainfall of less than 1.0 mm, averaged over rainfall stations with long-term records across the island.

[2] The Indian Ocean Dipole (IOD) refers to the sustained change to the difference between sea surface temperatures (SSTs) of the tropical western and eastern Indian Ocean. The IOD varies between three phases – positive, negative and neutral. A positive (negative) phase occurs when cooler (warmer) SSTs develop in the eastern Indian Ocean, resulting in below (above) normal rainfall in the eastern Indian Ocean and the surrounding region. More information on the IOD can be found at https://www.weather.gov.sg/LEARN_climate/.

CLIMATE STATION STATISTICS

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

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

Singapore, 2 August 2019 – The National Environment Agency’s (NEA) Meteorological Service Singapore (MSS) is forecasting drier-than-normal weather conditions in Singapore and the surrounding region, including Sumatra and Kalimantan, in the coming weeks. In recent days, persistent hotspot activities with smoke plumes have been observed in Riau and Jambi provinces in Sumatra and southern parts of Kalimantan. These conditions can lead to an escalation of hotspot activities and an increase in the risk of transboundary haze occurrence in Singapore and the surrounding region.

2      Since early July 2019, dry weather has been persisting over southern Sumatra and Kalimantan. Drier weather can be expected in the next three months (August to October), with monthly rainfall of up to 60% below average.

3     Singapore has likewise been experiencing dry and warm weather in recent weeks. The total rainfall recorded for July 2019 at the climate station in Changi is 92% below the long term average, breaking the record set in 1997 for the driest July in Singapore. July 2019 is also Singapore’s second warmest July on record, with an average temperature of 29.0°C.

Impact of the Indian Ocean Dipole

4     Neutral conditions (neither El Nino nor La Nina) currently prevail in the tropical Pacific Ocean, and are forecast to persist for the rest of the year. A key climate driver influencing the rainfall over Singapore and the surrounding region over the next few months is the Indian Ocean Dipole (IOD), which refers to the sustained change to the difference between sea surface temperatures (SSTs) of the tropical western and eastern Indian Ocean. The IOD varies between three phases – positive, negative and neutral. A positive (negative) phase occurs when cooler (warmer) SSTs develop in the eastern Indian Ocean, resulting in below (above) normal rainfall in the eastern Indian Ocean and the surrounding region. Each phase occurs every three to five years on average and typically lasts about six months.

5     The IOD is currently in its positive phase, which leads to drier weather over the areas adjacent to the eastern Indian Ocean, including Sumatra, Malaysia and Singapore. Major climate centres are predicting that the positive phase of the IOD is expected to persist over the coming months.

Risk of Transboundary Haze

6     Singapore may experience occasional occurrences of transboundary haze during the next few weeks to months. The likelihood of haze affecting Singapore is dependent on factors such as the proximity and extent of the fires, the direction and strength of the prevailing winds, and the incidence of rain.

7     MSS will continue to closely monitor the regional weather and haze situation, and provide updates when necessary. Updates on haze information are available on the MSS website at https://www.weather.gov.sg/warning-haze-satellite-image/.

Singapore, 16 July 2019 – The Southwest Monsoon conditions that have been prevailing over Singapore and the surrounding region since early June 2019 are forecast to continue for the rest of July 2019, and persist until October 2019. During this period, the low level winds are forecast to blow from the southeast or southwest.

2          In the second fortnight of July 2019, the monsoon rain band is forecast to lie over northern Southeast Asia and the northern South China Sea. This is expected to bring generally dry and occasionally windy conditions to Singapore and the surrounding region in the first week of the fortnight. Despite the drier conditions, there could still be a few days of localised short-duration showers at times with thunder over a few areas of the island in the late morning and early afternoon.

3          More rain can be expected in the later part of July 2019. Periods of widespread thundery showers, at times heavy can be expected on two or three days due to large scale wind convergence over Singapore and the surrounding region. In addition, there could be a few days of localised short-duration thundery showers in the late morning and early afternoon. Overall, the rainfall for July 2019 is likely to be slightly below normal.

4          In the second fortnight of July 2019, the daily temperature over Singapore is forecast to range between 25°C and 33°C. The daily maximum temperature could reach a high of around 34°C on some days. On some nights, warm and humid conditions with night-time temperatures of around 28°C are expected, in particular when prevailing winds blowing from the southeast bring warm and humid air from the sea.

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

REVIEW (1 – 15 July 2019)

6          Southwest Monsoon conditions prevailed in the first fortnight of July 2019, and the low level winds were blowing mostly from the southeast or southwest.

7          During the first half of July 2019, Singapore experienced short-duration thundery showers in the late morning and afternoon due to strong solar heating of land areas and large-scale convergence of winds in the surrounding vicinity. Most of the showers fell in the first half of the fortnight. The thundery showers that fell over many areas of the island on 8 July 2019 recorded a daily total rainfall of 51.6mm at Mandai. This was the highest daily total rainfall for July 2019 (as of 15 July 2019).

8          There were several warm days in the first fortnight of July 2019. The daily maximum temperature ranged between 31.1°C and 34.5°C, with the highest daily maximum temperature of 34.5°C recorded at Pulau Ubin on 6 July 2019. There were also a few warm nights where the night-time temperature hovered around 28°C, especially over the southeastern part of the island. The warm nights were due to warm and humid air blown in from the sea by the prevailing southeasterly winds.

9          Below-average rainfall was recorded over many parts of the island in the first fortnight of July 2019. The lowest anomaly of 94% below-average was recorded at Changi.

CLIMATE STATION STATISTICS

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

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

Short-duration thundery showers and Sumatra squalls mostly in first half of coming fortnight; Dry and warm conditions in the 2^nd week of month with warm temperatures of up to 35°C expected on some days.

Singapore, 1 July 2019 – The prevailing Southwest Monsoon conditions are expected to persist over Singapore and the surrounding region in the first fortnight of July 2019. During the period, the low level winds are forecast to blow from the southeast or southwest.

2          For the fortnight, showers are forecast mostly in the first week of July 2019. Short-duration thundery showers in the late morning and early afternoon are expected on three to five days. On two or three days, Sumatra squalls moving over the island could bring widespread thundery showers and gusty winds in the morning. Overall, the rainfall for the first fortnight of July 2019 is likely to be near-normal across the island.

3          During the first half of the month, the monsoon rain band is forecast to gradually shift further north away from the Equator, and a transition to drier conditions in the region can be expected in the next few weeks. For Singapore, the showers in the first week are forecast to ease, and dry and warm weather are expected in the second week of the month.

4          The daily temperature on most days in the coming fortnight is forecast to range between 25°C and 34°C, and the daily maximum temperature could reach a high of 35°C on some days. On some nights, minimum night-time temperatures of around 28°C can be expected, especially when the prevailing winds blow from the southeast and bring in warm and humid air from the sea.

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

REVIEW (1 – 30 June 2019)

6         In June 2019, Southwest Monsoon conditions prevailed over Singapore and the surrounding region, and the low level wind blew from the southeast or southwest.

7          June 2019 was a relatively wet month. Thundery showers fell over the island mostly between the late morning and afternoon on more than three-quarters of the month. The wet weather was due to the presence of the monsoon rain band over the equatorial region, the large-scale wind convergence over the surrounding region and/or the passage of the Madden-Julian Oscillation (MJO). In particular, on 3 June 2019, the widespread thundery showers that fell in the late morning and early afternoon recorded a rainfall total of 102.8mm at Bukit Merah. On 21 June 2019, the localised moderate to heavy thundery showers that fell over the eastern part of Singapore recorded a daily rainfall total of 137.7mm (at Changi). This was the highest daily total rainfall recorded for June 2019.

8          The wet weather in June 2019 also brought slightly cooler days to Singapore compared to May 2019. The mean daily maximum temperature of 31.3°C in June 2019 was 0.7°C below the long term mean for June. The daily maximum temperature in June 2019 ranged between 28.2°C and 33.9°C. The highest daily maximum temperature of 33.9°C was recorded at Choa Chu Kang and Pulau Ubin on 11 June 2019, and at Paya Lebar on 20 June 2019. There were a few warm nights in June 2019 where the minimum night-time temperature was around 28°C. This was due to prevailing winds blowing from the southeast that brought in warm and humid air from the sea.

9          Well above-average rainfall was received across the island in the first fortnight of June 2019. The highest anomaly of 92% above-average was at Jurong West. The anomaly was lowest at Admiralty at 7% below-average.

CLIMATE STATION STATISTICS

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

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

Singapore, 31 May 2019 – In the first fortnight of June 2019, the prevailing light and variable winds over Singapore and the surrounding region are forecast to strengthen and blow from the southeast or southwest. This signals the end of the inter-monsoon period and the start of the Southwest Monsoon season. The Southwest Monsoon season typically extends into September and is a generally drier season compared to other times of the year.

2          The weather in the first fortnight of June 2019 is forecast to be just as wet as it was in the last fortnight of May 2019. With strong day-time heating of land areas, thundery showers are expected mostly in the late morning and early afternoon on six to eight days. On two to three days in the coming fortnight, Sumatra squalls moving from the Strait of Malacca to the South China Sea could track over Singapore and bring widespread thundery showers and occasional gusty winds in the morning. The overall rainfall for the first half of June 2019 is likely to be above-normal over most parts of Singapore.

3          The warm and humid conditions in May 2019 are forecast to persist into the first fortnight of June 2019. With the setting in of the Southwest Monsoon season, more warm and humid nights can be expected; warm nights typically occur when the prevailing winds blow from the southeast and brings warm, humid air from the sea over the land. The daily temperature on most days is forecast to range between 25°C and 33°C. Night-time minimum temperatures of up to 28°C can be expected on some days.

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

REVIEW (1 – 30 May 2019)

5          Inter-monsoon conditions prevailed in Singapore and the surrounding region in May 2019. During this period, the low level prevailing winds were generally light and variable in direction, and on occasions, blew from the east or southeast.

6          In May 2019, thundery showers due to convergence of winds over Singapore and the surrounding vicinity, fell in the late morning and afternoon on most days. On several days, particularly in the second week of the month, the passage of Sumatra squalls brought widespread thundery showers to Singapore between the predawn and early morning. The thundery showers were heaviest on 16 May 2019 where the highest daily rainfall total recorded was 119.8mm at Jurong Pier. A waterspout, associated with an intense Sumatra squall, was sighted over the sea area south of Tanjong Pagar on 11 May 2019.

7          May is climatologically one of the warmest months of the year. In May 2019, the highest daily maximum temperature across the island was at least 34°C on more than half the number of days of the month. The highest daily maximum temperature of 35.0°C was recorded at Paya Lebar and Clementi on 6 and 7 May 2019 respectively. The lowest daily minimum temperature of 20.8°C was recorded at East Coast Park around predawn when a squall moved over Singapore on 8 May 2019.

8          At the climate station in Changi, May 2019’s mean monthly temperature of 29.3°C (as of 30 May 2019) is on track to tie with that in May 1997 and 2016 as the second warmest May in Singapore since temperature records started in 1929. In addition, May 2019’s mean daily minimum temperature of 26.5°C is likely to tie the record high set in May 2003 and 2016.

9          Slightly less than half of Singapore received above-average rainfall in May 2019, with most of the rain falling over the southwestern part of Singapore. The highest rainfall of 366.8 mm (78% above average) was recorded at Jurong. Rainfall was lowest over the eastern part of Singapore at Changi where 68.6 mm (56% below average) of rain was recorded.

CLIMATE STATION STATISTICS

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

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