Colombo features a tropical rainforest climate (Köppen climate classification *Af*). The city is warm and humid year-round, with average temperatures consistently hovering between 26°C and 31°C (79°F to 88°F). Because of its proximity to the equator, there is very little seasonal temperature variation.
The city's weather is primarily governed by the monsoon seasons. The Southwest Monsoon (Yala) brings heavy rainfall from May to August, while the Northeast Monsoon (Maha) affects the city from October to January. Despite these distinct rainy seasons, Colombo receives significant precipitation throughout the year, averaging around 2,500 millimeters annually.
Humidity is generally high, often exceeding 70%, which can make the air feel warmer than the recorded temperature. The best time to visit Colombo is typically during the drier months from January to March, when the skies are clear and the sea breezes provide a pleasant respite from the tropical heat. The city is generally shielded from tropical cyclones, though heavy monsoon deluges occasionally cause localized urban flooding.