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Singapore, 31 December 2021 – The prevailing Northeast Monsoon conditions in the region are forecast to persist into January 2022, with low-level winds blowing from the northwest or northeast. At the start of the new year, a high-pressure system over the northern Asian continent is expected to strengthen and bring wetter and cooler conditions to the region.

2    The strengthening of the high-pressure system is expected to bring a surge of strong north-easterly winds (or monsoon surge ) over the South China Sea. The surge will last for a few days and will likely bring cooler conditions with occasional spells of moderate to heavy thundery showers over Singapore and the surrounding vicinity. Thereafter, localised thundery showers are forecast in the afternoon. The rainy weather is likely to ease in the second week of the fortnight. Localised short-duration thundery showers can still be expected in the afternoon on several days, and warm and occasionally windy conditions with passing showers on a few days. Overall, the rainfall for the first half of January 2022 is expected to be slightly above average over most parts of the island.

3    The rainy weather in early January 2022 is likely to result in lower daily temperatures of between 23 °C and 31 °C on a few days. For the rest of the fortnight, the daily temperatures are forecast to range between 24°C and 33°C. The daily maximum temperature may still reach a high of up to 34oC on a few 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.

REVIEW (1 – 30 December 2021)

5    In December 2021, Northeast Monsoon conditions prevailed over Singapore and the surrounding region. During this period, the low-level winds blew from the northwest or northeast.

6    While December is climatologically a wetter month than November, December 2021 was drier compared to November 2021. The Northeast Monsoon brought relatively windy conditions with passing showers to Singapore and the surrounding region on most days in the first half of the month. Short-duration thundery showers fell over parts of the island in the afternoon on most days in the second half of December 2021. On a few days, large-scale convergence of winds over Singapore and the surrounding vicinity brought widespread moderate to heavy thundery showers. On the night of 18 December 2021, intense thundery showers fell over many parts of the island. The daily total rainfall recorded that day was 82.6 mm around the Pulau Ubin area. This was the highest total rainfall in a day for December 2021.

7    The daily temperature in December 2021 ranged between 22.1oC and 34.8oC. The highest daily maximum temperature of 34.8 °C was recorded on 1 December at Tengah. On 2 December 2021, the passage of a Sumatra squall brought rainy weather and cloudy skies to Singapore, and the minimum temperature at Jurong dropped to a low of 22.1°C.

8    At the Changi climate station, the daily maximum temperature of 33.9°C recorded on 1 December 2021 was the highest daily maximum temperature ever recorded at our climate station in December. The mean monthly temperature of 27.7°C (as of 30 Dec 2021) was 0.9°C warmer than the long-term December mean temperature.

9 Singapore received below-average rainfall in December 2021. The highest anomaly of 71% below average was recorded at Seletar. The lowest anomaly of 7% below average was at Jurong Pier.

CLIMATE STATION STATISTICS

Long-term Statistics for January
(Climatological reference period: 1991 – 2020)

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

Singapore, 16 December 2021 – The Northeast Monsoon conditions which prevailed since the start of December 2021 are expected to continue in the second half of the month, with winds blowing mainly from the northwest or northeast. 

2    The month of December is usually associated with wet weather and occasional windy conditions. However, the Northeast Monsoon conditions in the coming fortnight are forecast to be generally weak with fewer windy days as compared to the first half of the month. While the rest of December 2021 will likely be less rainy than usual, short-duration afternoon thundery showers can still be expected on most days. On some of these days, the showers may extend into the evening. In the first few days of the fortnight, the passage of Sumatra squalls may bring widespread rain, with occasional gusty winds, between the pre-dawn hours and morning. Overall, the rainfall for December 2021 is expected to be well below-average across the island.

3    For the next two weeks, the daily temperature is expected to range between 24°C and 33°C on most days, with highs of 34°C on a few days. The temperature may drop to 22 – 23 °C on a few rainy 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.

REVIEW (1 –  15 December 2021)

5    In the first half of December 2021, moderate to strong Northeast Monsoon conditions prevailed over Singapore and the surrounding region, and the low-level winds blew mainly from the northwest or northeast.

6    For the first fortnight of December 2021, the Northeast Monsoon brought relatively windy conditions with passing showers to Singapore and the surrounding region on most days, particularly in the second week of December 2021. The strongest wind gust of 68.3 km/hr was recorded at Admiralty on 13 December 2021. On 10 and 11 December 2021, the convergence of low-level winds in the surrounding region of Singapore triggered several spells of widespread rain across the island in the afternoon and evening. The highest daily total rainfall of 78.8mm was recorded at West Coast on 10 December 2021.

7    On 1 December 2021, a daily maximum temperature of 34.8°C was recorded at Tengah. This was the highest daily maximum temperature in the first half of December 2021. On the same day, the temperature at the Changi climate station reached a record high of 33.9 °C, surpassing the previous climate station record of 33.8 °C for the month of December. On 2 December 2021, the passage of a Sumatra squall brought rainy weather and cloudy skies to Singapore, and the minimum temperature at Jurong West dropped to a low of 22.1°C.

8    In the first half of December 2021, rainfall was well below-average across the whole island. The rainfall anomaly at MacRitchie Reservoir was 81% below average.

CLIMATE STATION STATISTICS

Long-term Statistics for December
(Climatological reference period: 1991 – 2020)

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

Singapore, 1 October 2021 –The weather for the first half of October 2021 is expected to be warm and less wet compared to September 2021. The daily maximum temperature is forecast to range between 33°C and 34°C on most days, with highs of around 35°C on a few days. Warm and humid conditions can be expected on a few nights with night-time temperatures of around 28°C.

2      During the next fortnight, the prevailing Southwest Monsoon conditions with low-level winds blowing from the southeast or southwest are forecast to persist. Around the end of the fortnight, the low-level winds are expected to weaken and become light and variable in direction, signalling the start of the inter-monsoon period around mid-October 2021.

3      On a few days in the early part of the fortnight, Singapore and the surrounding region can expect dry and warm conditions due to a mass of dry air moving eastward from the Indian Ocean over the equatorial Southeast Asia region. During the fortnight, short-duration thundery showers are expected on a few days over parts of the island between the late morning and afternoon due to strong day-time heating of land areas. In the latter half of the fortnight, a low-pressure system is forecast to develop over the South China Sea. This could result in large scale convergence of winds over Singapore and the surrounding vicinity and trigger the development of Sumatra squalls over the Strait of Malacca. The squalls can bring widespread thundery showers and gusty winds over Singapore on some days between the early and pre-dawn hours, as they move east toward the South China Sea. The rainfall for first half of October 2021 is forecast to be below average over parts of the island.

4      In the first half of October 2021, it is expected to be warm on most days and the daily temperature is expected to range between 24°C and 34°C. On a few days, particularly when it is dry and warm, the daily maximum temperature could reach a high of around 35°C. The weather on some nights can be warm when prevailing winds blow from the southeast or south, bringing warm and humid air from the sea over the land. Night-time temperatures of around 28°C can be expected on these nights.

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.

REVIEW (1 – 30 September 2021)

6      Southwest Monsoon conditions prevailed over Singapore and the surrounding region in September 2021. The low-level winds blew from the southeast or southwest on most days and were light and variable in direction on a few days.

7      On most days in September 2021, thundery showers fell over parts of Singapore in the late morning and afternoon due to strong daytime heating of land areas and/or convergence of winds over Singapore and the surrounding vicinity. On some of these days, the showers extended into the evening. The passage of Sumatra squalls from the Strait of Malacca toward the South China Sea brought thundery showers over Singapore between the early hours and morning on some days. On 2 September 2021, large-scale convergence of prevailing winds over Singapore and the surrounding region led to the development of a Sumatra squall over the Strait of Malacca. The squall brought island-wide moderate to heavy thundery showers and gusty winds in the early and predawn hours. The highest daily total rainfall of 123.6mm recorded at Ang Mo Kio that day was the highest daily total rainfall for September 2021.

8      In September 2021, there were 10 days where the daily maximum temperature was 34.0°C or higher. The highest daily maximum temperature of 34.8°C was recorded at Sentosa on 17 September 2021. The lowest daily minimum temperature of 22.0°C was recorded at Tengah on 7 September 2021.

9      Rainfall was above average over all parts of the island in September 2021. The highest anomaly of 91% above average was recorded at Mandai. The anomaly was lowest at Tanjong Katong at 19% above average.

CLIMATE STATION STATISTICS

Long-term Statistics for October
(Climatological reference period: 1991 – 2020)

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

Singapore, 16 September 2021 – The weather for the rest of September 2021 is forecast to be similar as that in the first fortnight of the month, with thundery showers expected on most days. For the coming fortnight, the daily maximum temperature is forecast to range between 32°C and 33°C on most days, and with daily highs of around 34°C on a few days.

2      The prevailing Southwest Monsoon conditions in the region are forecast to persist for the rest of September 2021. During the period, the low-level winds are expected to blow mostly from the southeast or southwest, and occasionally shift to blow from the south in the later part of the month.

3      On most days in the coming fortnight, short-duration thundery showers are forecast over parts of the island between the late morning and afternoon. In addition, with a low-pressure system forecast to develop over the northern South China Sea, this could trigger the development of Sumatra squalls over the Strait of Malacca and bring widespread thundery showers and gusty winds to Singapore between the predawn and morning on some days. The overall rainfall for September 2021 is forecast to be above average over most parts of the island.

4      During the second fortnight of September 2021, the daily temperature is forecast to range between 24°C and 33°C on most days. There could still be a few warm days with the daily maximum temperature reaching around 34°C. The weather during the night can be warm and humid with minimum night-time temperatures of around 28°C particularly over the south-eastern parts of the island. This occurs when the prevailing southeast winds bring warm and humid air from the sea over the land.

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.

REVIEW (1 – 15 September 2021)

6      In the first fortnight of September 2021, Southwest Monsoon conditions prevailed over the region. During this period, the low-level winds blew from the southeast or southwest.

7      In the first two weeks of September 2021, thundery showers fell over parts of the island in the afternoon on most days due to strong day-time heating of land areas. On a few days, the eastward passage of Sumatra squalls from the Strait of Malacca toward the South China Sea brought thundery showers over Singapore in the predawn and early morning. On 2 September 2021, large-scale convergence of winds in the surrounding vicinity led to the development of a Sumatra squall over the Strait of Malacca. The passage of the squall brought widespread moderate to heavy thundery showers and gusty winds over Singapore in the early and predawn hours. The highest daily total rainfall recorded that day was 123.6mm at Ang Mo Kio. This was the highest daily total rainfall for the first half of September 2021. At the Changi climate station, the total rainfall recorded in the first two weeks of September 2021 (up to 15 September 2021) was 119.2mm, which is close to the average monthly rainfall of 124.9mm for September.

8      The rainy weather and cloudy skies in the first fortnight of September 2021 brought relatively cool conditions on most days. There were four days in the fortnight where the daily maximum temperature was above 34.0°C. The highest daily maximum temperature of 34.5°C was recorded at Marina Barrage on 5 September 2021 and the lowest daily minimum temperature of 22.0°C was recorded at Tengah on 7 September 2021.

9      Rainfall was above average over all parts of the island in the first half of September 2021. The highest anomaly of 108% above average was recorded at Jurong Pier. The anomaly was lowest at Sembawang at 17% above average.

CLIMATE STATION STATISTICS

Long-term Statistics for September
(Climatological reference period: 1991 – 2020)

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

Singapore, 1 September 2021 – The weather in the first fortnight of September 2021 is expected to be less wet with a few warm days compared to the second fortnight of August 2021. In the coming fortnight, the prevailing Southwest Monsoon conditions are forecast to persist over Singapore and the surrounding region, and the low-level winds are expected to blow from the southeast or southwest.

2    In the first half of September 2021, the monsoon rain band is expected to lie over the equatorial Southeast Asia region. Short-duration thundery showers are forecast between the morning and early afternoon over some parts of Singapore on most days. On a few days, Sumatra squalls from the Strait of Malacca may bring widespread thundery showers with occasional gusty winds over Singapore between the early and pre-dawn hours, as they move eastward toward the South China Sea. On one or two days, widespread moderate to heavy thundery showers can be expected when prevailing winds in the region converge over Singapore and the surrounding region. The total rainfall for first half of September 2021 is forecast to be above average over most parts of the island.

3    During the fortnight, the daily temperature on most days is expected to range between 24°C and 33°C. On one or two rainy days, the daily minimum temperature may dip to around 22°C. In the latter half of the fortnight, the daily maximum temperature could reach a high around 34°C on a few days. On some nights, warm and humid conditions can be expected when prevailing winds from the southeast or south blow warm and humid air from the sea. The minimum night-time temperatures may reach around 28°C, particularly over the south-eastern parts of the island.

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.

REVIEW (1 – 31 August 2021)

5      In August 2021, Southwest Monsoon conditions prevailed over the region, and the low-level winds blew from the southeast or southwest on most days, and from the east on a few days.

6      August 2021 was a relatively wet month with well-above average rainfall recorded across the island. The wet weather can be attributed to the influence of the negative phase of Indian Ocean Dipole (IOD) ^[1] , the convergence of surrounding winds, as well as the passage of a wet phase of Madden-Julian Oscillation (MJO) ^[2] over the equatorial region.

7      In August 2021, there were several days where the rain was heavy over some parts of the island. On the morning of 20 August 2021, convergence of prevailing winds from the south and west-northwest brought widespread moderate to heavy thundery showers over the island. The rain was heaviest over the central, northern, and eastern parts of Singapore, and more than 100mm of rain fell over several areas including Hougang, Choa Chu Kang, Pasir Ris, and Ang Mo Kio that morning. On 24 August 2021, a few spells of widespread moderate to heavy thundery showers fell over the island in the pre-dawn hours and morning, followed by light to moderate rain in the afternoon. The highest daily total rainfall recorded that day was 247.2mm at Mandai. This is the highest daily total rainfall for August 2021 and has surpassed the record highest daily total rainfall of 181.8mm (at Changi on 22 August 1983) for August.

8      Based on the rainfall averaged over long-term stations island-wide, August 2021 is the wettest August since 1980, with a monthly total rainfall of 426.2mm. This has surpassed the record highest August rainfall of 346.6mm set in August 1996. At the Changi climate station, the total rainfall for August 2021 was 293.6mm, which is the second highest August rainfall after August 2008 (at 327.3mm) since 1980. The Changi climate station also recorded a total of 24 rain days in August 2021, well above the long-term average of 14 days for August.

9      In August 2021, the daily maximum temperature was below 34.0°C on most days due to the rainy weather. The lowest daily minimum temperature was 21.3°C recorded at Newton on 24 August 2021. There were a few warm days mainly in the first half of August 2021, and the highest daily maximum temperature recorded in August 2021 was 34.9°C at Marina Barrage on 3 August 2021.

10      Rainfall in August 2021 was well-above average across the island, with most of the rain falling in the northern and western parts of Singapore. The highest anomaly of 240% above average was recorded at Bukit Panjang.

^[1] The IOD refers to the sustained change to the different between sea surface temperatures (SSTs) of the tropical western and eastern Indian Ocean. The IOD varies between three phases – positive, negative and neutral. A negative phase occurs when warmer SSTs develop in the eastern Indian Ocean, resulting in above average rainfall over Singapore and the surrounding region.

^[2] The MJO is characterised by a large-scale “pulse” of rain clouds that move eastward around the equator with a typical cycle of 30-60 days.

CLIMATE STATION STATISTICS

Long-term Statistics for September
(Climatological reference period: 1991 – 2020)

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