Expect More Wet Weather in First Fortnight of November 2018

1st fortnight of Nov 2018 to be wetter than last fortnight of Oct 2018. Expect thundery showers on 7–9 days mostly in afternoon but may extend into evening on few days, Widespread rain with gusty winds on 2 or 3 mornings due to Sumatra squalls.

Singapore, 1 November 2018 – Inter-monsoon conditions have set in over Singapore and the surrounding region since late October 2018, and are expected to persist into the first fortnight of November 2018. During the period, the prevailing winds over the region are forecast to be light and variable in direction.

2           The first fortnight of November 2018 is expected to be wetter than the last fortnight of October 2018. On seven to nine days in the first two weeks of November, the prevailing light wind conditions coupled with strong solar heating of land areas during the day is expected to bring moderate to heavy thundery showers over Singapore. These thundery showers are expected to fall mostly in the afternoon, and on a few of these days, the showers may extend into the evening. In addition, on two or three days in the fortnight, widespread thundery showers accompanied with gusty winds are expected over Singapore in the morning due to the passage of Sumatra squalls moving across Singapore from the Strait of Malacca. Frequent lightning activity can also be expected during the first fortnight of the month. Based on long-term statistics, November is the second wettest month in the year after December.  Rainfall for the first fortnight of November 2018 is likely to be above normal.

3          In the first fortnight of November 2018, the daily temperature is expected to range between 24°C and 33°C on most days.  On days with widespread rainfall, the minimum daily temperature could fall to a range between 22 and 24°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, or the MSS’ Weather@SG app.

REVIEW (1 – 31 October 2018)

5         Southwest Monsoon conditions prevailed during first half of October 2018 with the low level winds blowing mainly from the southeast or southwest. In the second half of the month, the low level winds gradually weakened and was light and variable in direction from late October 2018, which signalled the onset of the inter-monsoon period.

6         October 2018 was a generally wet month where thundery showers fell over the island on most days from the second to the last week of the month. The first week of October 2018 was dry and warm. The wet conditions during the month were due to the occurrence of persistent easterly winds that brought moisture from the tropical central Pacific Ocean to the southern Southeast Asia region between 6 and 14 October, and localised sea breeze convergence in the latter half of the month. The highest daily total rainfall recorded in October 2018 was 109.8mm at Sentosa on 9 October 2018. In the second fortnight of October 2018, the highest daily total rainfall recorded was 98mm over Seng Kang. This was the second highest daily rainfall total recorded for October 2018.

7         The daily temperature in October 2018 ranged from 22.5°C to 35.6°C. In the first week of October 2018 where dry and warm conditions were experienced, there were 6 days where the daily maximum temperature recorded was above 34°C. The daily maximum temperature in the first week of October ranged between 32.5°C and 35.6°C. The highest daily maximum temperature of 35.6°C was recorded on 5 October 2018 at Marina Barrage. For the rest of the month where it rained on most days, the daily maximum temperature ranged between 28.4°C and 35.2°C. The lowest daily maximum temperature of 28.4°C was recorded on 14 October 2018 at Choa Chu Kang. For October 2018, the daily minimum temperature ranged between 22.5°C and 26.5°C.

8       The rainfall recorded in October 2018 was well above average over many parts of the island. The highest rainfall of 423.8 mm (101% above average) was recorded at Lim Chu Kang, and the lowest rainfall of 166.2mm (26% below the average) was recorded at Ulu Pandan.

Fortnightly Nov

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)