Singapore's Monsoon Seasons
Just north of the equator, Singapore stays hot and humid all year — so instead of four temperate seasons, its weather is organised by the monsoons and the transitions between them.
Four phases, not four seasons
Singapore's year runs through the Northeast Monsoon, an inter-monsoon period, the Southwest Monsoon, and a second inter-monsoon period. Each has a distinct wind direction and storm character, even though temperatures barely change.
Northeast Monsoon (December to early March)
Winds blow from the northeast. The early part (December and January) is the wettest, windiest stretch of the year, prone to monsoon surges — bursts of strong, cool wind that bring days of continuous rain and the island's most widespread flooding. It is also slightly cooler and cloudier than the rest of the year. The later part (February to early March) often turns drier.
First inter-monsoon (late March to May)
Winds go light and variable as the monsoon reverses. Intense afternoon and early-evening thunderstorms become common, driven by strong daytime heating and sea breezes. This period brings frequent lightning and some of the year's highest temperatures.
Southwest Monsoon (June to September)
Winds swing to the southeast and south. This is the season of the Sumatra squall — pre-dawn and morning lines of thunderstorms sweeping in from the west. Short "dry spells" also occur, and, in some years, this is when regional fires push transboundary haze over the island.
Second inter-monsoon (October to November)
Winds again turn light and variable. Like the first inter-monsoon, afternoon thunderstorms are frequent and often intense, with heavy rain and vigorous lightning as the pattern transitions back toward the northeast.
The year at a glance
| Period | Months | Character |
|---|---|---|
| Northeast Monsoon | Dec–early Mar | Wettest early on; monsoon surges, cooler, flooding |
| Inter-monsoon | Late Mar–May | Afternoon storms, lightning, hottest days |
| Southwest Monsoon | Jun–Sep | Sumatra squalls, dry spells, haze risk |
| Inter-monsoon | Oct–Nov | Frequent intense afternoon thunderstorms |
Note that Singapore is wet year-round — there is no true dry season, only shifts in how and when the rain and storms arrive.