Late Southwest Monsoon

September weather in Singapore

One of the drier months. Sumatra squalls still occur. Haze can linger if the dry season is strong over Sumatra and Kalimantan.

August October

Mean temperature

28°C

25.2 to 31.6°C

Rainfall

124.9 mm

13 rain days

Humidity / wind

80.7%

2.1 m/s mean wind

Thunder / lightning

14 / 12

days in a typical month

Compared with the year

  • Rain vs annual monthly share6%
  • Hottest month of the yearMay (28.6°C)
  • Wettest month of the yearDecember (331.9 mm)
  • Driest month of the yearFebruary (105.1 mm)

Normals from Changi Climate Station, 1991-2020.

What to check this month

240 km radar Haze situation Air quality
Dark squall line approaching a tropical coast
A Sumatra squall is a line, not a blob. It usually arrives from the west.

What September actually feels like

  • One of the drier months. Squalls still happen. Haze can linger if the dry season is strong.
  • Useful month for outdoor plans, with a morning radar check as insurance.
  • Southwest flow is fading. Lightning starts to climb again toward October.

Monthly rainfall at Changi

1991-2020 normals. December is more than three times as wet as February.

Values in millimetres. Source: Meteorological Service Singapore.

All months

January February March April May June July August September October November December