Less Wet Weather and Warm Conditions Expected in First Half of October 2021

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 (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.





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

Average daily maximum temperature: 31.8 °C
Average daily minimum temperature: 25.0 °C
Average monthly temperature: 27.9 °C
Average rainfall: 168.3 mm
Average number of rain days: 15


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

Highest monthly mean daily maximum temperature: 33.0 °C (2002)
Lowest monthly mean daily minimum temperature: 22.8 °C (1964)
Highest monthly rainfall ever recorded: 497.1 mm (1942)
Lowest monthly rainfall ever recorded: 10.8 mm (2002)