Fortnightly Weather Outlook for 31 December 2020 – 15 January 2021
Singapore, 31 December 2020 – The prevailing Northeast Monsoon conditions in the region are forecast to persist into January 2021, 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 strengthen and bring cooler conditions over the region.
2 In the first week of the year, with the strengthening of the high-pressure system, a surge of strong north-easterly winds (or monsoon surge) is expected over the South China Sea. This is forecast to bring windy and cooler conditions with periods of moderate to heavy showers over Singapore and the surrounding vicinity on two to three days.
3 On most days in the fortnight, moderate thundery showers due to strong solar heating of land areas are expected in the afternoon and may extend into the evening on some days. On a few days, large-scale convergence of winds in the region could bring heavy and widespread thundery showers over the island. Overall, the rainfall for first half of January 2021 is expected to be above average over most parts of the island.
4 The monsoon surge in early January 2021 is also expected to bring cooler daily temperatures of between 22 °C and 31 °C on a few days. For the rest of the fortnight, the daily temperatures are forecast to range between 23 °C and 33 °C. The daily maximum temperature may still reach a high of up to 34 °C on one or two days.
REVIEW (1 – 30 December 2020)
6 In December 2020, Northeast Monsoon conditions prevailed over Singapore and the surrounding region. During this period, the low-level winds blew from the northwest or northeast.
7 During the month, short-duration moderate to heavy thundery showers fell over the island mostly between the afternoon and evening. On a few days, the showers extended into the night. On 26 December 2020, strong solar heating of land areas coupled with localised convergence of winds brought heavy thundery showers over many parts of the island. The daily total rainfall recorded that day was 108.4mm at Mandai. This was the highest total rainfall in a day for December 2020.
8 The daily temperature in December 2020 ranged between 22.2 °C and 35.1 °C . The highest daily maximum temperature of 35.1 °C was recorded on Christmas Day at Admiralty. The lowest daily minimum temperature of 22.2 °C was recorded at Sembawang on 28 December 2020. While it rained over the island on most days of the month, the mean monthly temperature of 27.2 °C for December 2020 at the Changi climate station was 0.8 °C higher than the month’s long-term average.
9 Many parts of the island recorded near average rainfall in December 2020, except for a few parts of western Singapore where rainfall was below average. Around the Choa Chu Kang area, rainfall was 39% below average.
CLIMATE STATION STATISTICS
Long-term Statistics for January
(Climatological reference period: 1981 – 2010)
|Average daily maximum temperature||30.4 °C|
|Average daily minimum temperature||23.9 °C|
|Average monthly temperature||26.5 °C|
|Average rainfall||234.6 mm|
|Average number of rain days||13|
Historical Extremes for January
(Rainfall since 1869 and temperature since 1929)
|Highest monthly mean daily maximum temperature:||31.8 °C (1998, 2016)|
|Lowest monthly mean daily minimum temperature:||21.6 °C (1934)|
|Highest monthly rainfall ever recorded:||818.6 mm (1893)|
|Lowest monthly rainfall ever recorded:||15.4 mm (1997)|