Wet Weather to Continue for the Second Half of November 2021

Singapore, 16 November 2021 – Inter-monsoon conditions with low-level winds that are light and variable in direction, are expected to continue for most of November 2021.  Towards the end of the month, the winds are forecast to gradually strengthen and shift to blow from the northeast or northwest.

2    The monsoon rain band is forecast to continue to lie over the equatorial Southeast Asia region for the rest of the month. During this period, short-duration moderate to heavy thundery showers are expected over parts of the island in the afternoon on most days. On some of these days, the thundery showers could extend into the evening. The thundery showers may be intense on one or two days as prevailing winds converge around the surrounding region of Singapore. On a few occasions, convergence of winds from the southwest or west over the Strait of Malacca may trigger the development of Sumatra squalls. The squalls are expected to bring widespread thundery showers and gusty winds over Singapore between the pre-dawn hours and morning as they move eastward toward the South China Sea. While the second half of November 2021 is not expected to be as wet as the first half, the overall rainfall for the month is forecast to be above average over most parts of Singapore.

3     In the second fortnight of November 2021, the daily temperature is forecast to range between 24°C and 33°C on most days, and may reach around 34°C on some days when there is less cloud cover.

4      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 –  15 November 2021)

5     In the first fortnight of November 2021, inter-monsoon conditions prevailed over Singapore, with prevailing winds generally light and variable in direction. On some days, the low-level winds shifted to blow from the southwest or west.

6     The monsoon rain band was located over the equatorial Southeast Asia region, and brought wet weather over Singapore on most days. Thundery showers occurred over most parts of Singapore mainly in the afternoon. On a few days, the passage of Sumatra squalls brought widespread showers with occasional gusty winds to Singapore between the early hours and morning. On 4 November 2021, strong solar heating of land areas coupled with convergence of winds in the surrounding region led to the development of intense thundery showers over Singapore. A total of 118.2mm of rainfall was recorded at Sembawang that day. This was the highest daily rainfall recorded for the first half of November 2021.

7      In the first half of November 2021, there were 5 days when the daily maximum temperature was 34°C or higher. The highest daily maximum temperature of 34.8°C was recorded at Paya Lebar on 14 November 2021. On 12 November 2021, the passage of a Sumatra squall brought cool and cloudy weather to Singapore, and the minimum temperature at Newton dropped to a low of 22.1°C.

8      Most parts of the island received near to above average rainfall in November 2021, except in western Singapore where the rainfall was below average. The highest anomaly of 58% above average rainfall was recorded at Sembawang, while 29% below average rainfall was recorded at Boon Lay.






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

Average daily maximum temperature: 31.2 °C
Average daily minimum temperature: 24.6 °C
Average monthly temperature: 27.2 °C
Average rainfall: 252.3 mm
Average number of rain days: 19


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

Highest monthly mean daily maximum temperature: 32.3 °C (2019)
Lowest monthly mean daily minimum temperature: 22.4 °C (1933)
Highest monthly rainfall ever recorded: 521.5 mm (1874)
Lowest monthly rainfall ever recorded: 53.5 mm (1981)