Singapore Climate

Singapore is 1 degree north of the equator. Singapore's climate is classified as tropical rainforest climate (Koppen climate classification Af), with no true distinct seasons. Owing to its geographical location and maritime exposure, its climate is characterized by uniform temperature and pressure, high humidity and abundant rainfall. The average annual rainfall is around 2,340 mm (92.1 in). The highest 24-hour rainfall figures ever recorded in history was 512 mm (20.2 in) (1978), 467 mm (18.4 in) (1969) and 366 mm (14.4 in) (19 December 2006).[1] The temperature hovers around a diurnal range of a minimum of 23 °C (73.4 °F) and a maximum of 32 °C (89.6 °F). May is the hottest month of the year in Singapore, followed by April. This is due to light winds and strong sunshine during those months.[2] The highest recorded temperature is 37.8 °C (100.0 °F) on 26 March 1998.[3] The lowest recorded temperature is 19.4 °C (66.9 °F) on 31 January 1934.

Relative humidity has a diurnal range in the high 90s in the early morning to around 60% in the mid-afternoon, but does go below 50% at times. In May 2009, the average relative humidity was 81%, an increase over the figure of 77.1% in May 2008. During prolonged heavy rain, relative humidity often reaches 100%. Generally, there is much more rainfall on the western side of the island than on the eastern portion of Singapore, owing to a rain shadow effect. Thus, the eastern side of Singapore is much drier and slightly hotter than western Singapore. This can cause slight weather disparities from one side of the island to the other. This is significant to note because even a small hill such as Bukit Timah can cause this phenomenon. Despite Singapore's small size, there may be sunshine on one side while there is rain on the other.

Further contrasts that prevent true all-year uniformity are the monsoon seasons which happen twice each year. The first one is the Northeast Monsoon which occurs from December to early March. The second is the Southwest Monsoon season which occurs from June to September. Periods between monsoon seasons receive less rain and wind. During the Northeast Monsoon, northeast windsprevail, sometimes reaching 20 km/h (12 mph). There are cloudy conditions in December and January with frequent afternoon showers. Spells of widespread moderate to heavy rain occur lasting from 1 to 3 days at a stretch. It is relatively dry in February till early March although rainfall still exceeds 120mm. It is also generally windy with wind speeds sometimes reaching 30 to 50 km/h (19 to 31 mph) in the months of January and February. During the Southwest Monsoon season, southeast/southwest winds prevail. Isolated to scattered showers occur in the late morning and early afternoon. Early morning "Sumatra" squall lines are common.

Weather chart