More Thundery Showers Expected in the First Half of August 2021

Singapore, 2 August 2021 – In the first fortnight of August 2021, more thundery showers are expected compared to the last fortnight of July 2021. During the period, the prevailing Southwest Monsoon conditions are expected to persist over Singapore and the surrounding region, with low-level winds forecast to continue blowing from the southeast or southwest.

2    In the first fortnight of August 2021, the monsoon rain band is forecast to lie close to the Equator. This is expected to bring more rainfall over the equatorial Southeast Asia region. On most days in the fortnight, short-duration thundery showers are expected between the late morning and afternoon over parts of the island. On some of these days, the thundery showers could be heavy due to strong day-time heating of land areas coupled with convergence of winds over Singapore and the surrounding vicinity. On a few days in the fortnight, the passage of a Sumatra squall is expected to bring widespread thundery showers with gusty winds to Singapore between the predawn hours and morning. The rainfall for the first fortnight of August 2021 is forecast to be above average over most parts of the island.

3     While more showers are expected in the coming fortnight, there could still be a few warm days with daily highs of around 34°C. On most days, the daily temperature is forecast to range between 24°C and 33°C. On a few nights, it can be relatively warm and humid when southeast winds blow warm and humid air from the sea toward land. Night-time minimum temperatures of up to 28°C can be expected, particularly over the eastern and southern coastal areas of the island.

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 – 31 July 2021)

5      In July 2021, Southwest Monsoon conditions prevailed over Singapore and the surrounding region, and the low-level winds blew mostly from the southeast or southwest. There were some days when the winds blew from the west.

6      The first half of July 2021 was much wetter than the second half of the month. Thundery showers fell over parts of the island between the late morning and afternoon on most days due to strong day-time heating of land areas. Large scale convergence of winds over Singapore and the surrounding region brought moderate to heavy thundery showers on a few days. On  12 and 13 July 2021 in particular, there were several spells of widespread moderate to heavy thundery showers with occasional gusty winds over Singapore. The daily total rainfall of 114.2mm recorded at Bukit Panjang on 13 July 2021 was the highest daily total rainfall for July 2021. The highest daily total rainfall on 12 July was 100.2mm at Ulu Pandan.

7       In July 2021, there were 14 days with daily maximum temperatures above 34°C. Most of these days were in the second half of the month where the weather was generally dry and warm. There were also several warm nights, particularly over the southern and south-eastern parts of the island where the night-time minimum temperature was around 28.0°C.

8       The highest daily maximum temperature for July 2021 was 35.2°C recorded at Marina Barrage on 30 July 2021. The lowest daily minimum temperature of 22.5°C was recorded at Admiralty on 13 July 2021.

9       The rainfall was above average over many parts of the island in July 2021. The highest rainfall anomaly of 108% above average was recorded at Tai Seng. The anomaly was lowest at Tuas at 22% below average.

 

 

CLIMATE STATION STATISTICS

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

Average daily maximum temperature 31.4 °C
Average daily minimum temperature 25.3 °C
Average monthly temperature 28.1 °C
Average rainfall 146.9 mm
Average number of rain days 14

 

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

Highest monthly mean daily maximum temperature: 32.7 °C (2019)
Lowest monthly mean daily minimum temperature: 23.0 °C (1962)
Highest monthly rainfall ever recorded: 526.8 mm (1878)
Lowest monthly rainfall ever recorded: 11.8 mm (2019)