More Thundery Showers Expected in Next Fortnight with Onset of Inter-Monsoon Conditions

Inter-monsoon conditions with light and variable winds expected in 2nd fortnight of April 2020.  Expect more short-duration moderate to heavy thundery showers accompanied with high lightning activity. A few warm days with max temp around 35°C expected.


Singapore, 15 April 2020 – According to the Meteorological Service Singapore, more thundery showers can be expected over Singapore in the second fortnight of April 2020. This is due to the onset of inter-monsoon conditions and the presence of the monsoon rain band over the equatorial Southeast Asia region during the period. The current warm weather is also expected to continue for the rest of the month.

2          In the second fortnight of April 2020, the low-level winds blowing from the northwest or northeast are forecast to gradually weaken and become light and variable in direction. This signals the cessation of the Northeast Monsoon season and the start of the inter-monsoon period, which is forecast to extend into May 2020.

3          April is typically a month with high lightning activity, and also one of the warmest months of the year. In the early part of the coming fortnight, a brief intrusion of a dry air mass extending from the South China Sea to the equatorial Southeast Asia region is expected to bring dry and warm weather to Singapore. On most days in the fortnight, short-duration thundery showers with frequent lightning are expected between the late morning and afternoon. On one or two of these days, the thundery showers could extend into the evening. The thundery showers are due to strong daytime heating of land areas coupled with convergence of winds over Singapore. Overall, the rainfall for April 2020 is expected to be above-normal over most parts of the island.

4          While more showers are forecast in the coming fortnight, warm conditions can still be expected on some days. The daily temperatures are expected to range between 24°C and 34°C on most days. On a few days during the fortnight, the daily maximum temperature could reach a high of around 35°C.

5         For updates of the daily weather and haze situation, please visit the MSS website (, NEA website (, or download the myENV app, MSS’ Weather@SG app, and the haze microsite (


REVIEW (1 – 14 April 2020)

6          In the first fortnight of April 2020, weak Northeast Monsoon conditions prevailed and the low-level winds over Singapore and the surrounding region blew from northwest or northeast.

7          Warm weather continued to prevail in the first two weeks of April 2020. During this period, the daily maximum temperature exceeded 34.0°C on most days. On six of these days, the daily maximum temperature was at least 35.0°C, with the highest temperature of 35.8°C recorded at Clementi on 10 April 2020.

8          More rain fell over Singapore in the first fortnight of April 2020 compared to the last fortnight of March 2020. Most of the thundery showers occurred in the afternoon due to strong solar heating of land areas. On 7 April 2020, large-scale wind convergence over the surrounding region triggered a Sumatra squall which brought widespread heavy showers to many parts of Singapore in the early and predawn hours. The daily total rainfall recorded that day was 115mm at Tuas, which is the highest recorded for the first fortnight of April 2020.

9          Most parts of the island recorded above-average rainfall in April 2020. The rainfall recorded at Kranji was 91% above-average while that recorded at MacRitchie was 36% below-average.







Long-term Statistics for April
(Climatological reference period: 1981 – 2010)

Average daily maximum temperature 32.3 °C
Average daily minimum temperature 25.0 °C
Average monthly temperature 28.0 °C
Average rainfall 154.8 mm
Average number of rain days 14


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

Highest monthly mean daily maximum temperature: 33.9 °C (1983)
Lowest monthly mean daily minimum temperature: 23.1 °C (1934)
Highest monthly rainfall ever recorded: 454.9 mm (1900)
Lowest monthly rainfall ever recorded: 16.6 mm (1977)