Onset of Northeast Monsoon Expected in Late November 2017

Northeast Monsoon to arrive in late Nov’17, and last till Mar’18. Wet weather expected in the next fortnight.

Singapore, 16 November 2017 – In the second fortnight of November 2017, the prevailing inter-monsoon conditions are expected to transition to the Northeast Monsoon. The prevailing light and variable low level winds are forecast to gradually strengthen and blow predominantly from the northwest or northeast towards the end of the month. This marks the onset of the Northeast Monsoon season which is expected to extend till March 2018.

2          The wet weather conditions experienced in the first fortnight of the month are expected to persist in the second half of November 2017. During this period, moderate to heavy thundery showers are forecast mostly in the afternoon on six to eight days, and may extend into the evening on a few of these days. In addition, widespread thundery showers accompanied by gusty winds can be expected between the predawn and early morning on one or two days. November is normally the second wettest month of the year with December being the wettest. The rainfall for November 2017 is likely to be well-above average for most parts of Singapore.

3          The daily temperature on most days in the second half of November 2017 is forecast to range between 24°C and 33°C. There could be a few warm days in the last two weeks of November 2017 where the daily maximum temperature could reach a high of around 34°C. On a few days when rain is expected to fall over most parts of the day, the daily minimum temperature could reach a low of around 22°C.

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, MSS’ Weather@SG app.

REVIEW (1 – 15 November 2017)

5          Inter-monsoon conditions prevailed over Singapore and the surrounding region in the first fortnight of November 2017. The low level winds during this period were generally light and variable in direction.

6          On most days in the past fortnight, there were moderate to heavy thundery showers in the afternoon due to strong solar heating of land areas. In addition, the passage of Sumatra squalls on several days brought widespread thundery showers with gusty winds to Singapore between the predawn hours and morning. In the first fortnight of November 2017, the highest daily rainfall of 130.6mm was recorded on 14 November 2017 around the East Coast area. This was due to the passage of an intense Sumatra squall over the island bringing widespread rain for most parts of the day.

7          During the first half of November 2017, the daily maximum temperature was between 28.5°C and 33.8°C, except for 15 November 2017 where the temperature reached a high of 34.1°C in the northern part of the island. The rainy weather during this period brought several days of cool night-time temperatures, with the daily minimum temperature ranging between 22.5°C and 24°C.

8          Most parts of Singapore received above normal rainfall in the first fortnight of November 2017. The highest rainfall of 382.2mm (190% above average) was recorded around the Seletar area. Rainfall was lowest around the Jurong area where 95.2mm (27% below average) was recorded.

Rainfall Anomaly 1-15 Nov 2017



CLIMATE STATION STATISTICS FOR November (Climatological reference period: 1981 – 2010)

Mean daily maximum temperature 31.1 °C
Mean daily minimum temperature 24.3 °C
Mean monthly temperature 27.0 °C
Mean rainfall for the month 258.5 mm
Mean number of rain days 18
Highest monthly mean daily maximum temperature 32.0 °C (1997)
Lowest monthly mean daily minimum temperature 23.6 °C (1981, 1983, 1991)
Highest monthly rainfall 508.4 mm (1989)
Lowest monthly rainfall 53.5 mm (1981)