Quick answer
Colombo is hot and humid all year, with daytime highs of about 30 to 32 °C and nights of about 24 to 26 °C. It receives roughly 2,300 to 2,400 mm of rain a year. January and February are the driest months, with roughly 60 to 100 mm each. April brings storms, May is often the wettest month as the southwest monsoon arrives, June to September have monsoon showers, and October and November bring heavy afternoon storms. December is drying.
Key takeaways
- Colombo is hot and humid all year, around 30 to 32 °C by day.
- January and February are the driest months, with roughly 60 to 100 mm of rain each.
- May and October are usually the wettest months, each with roughly 300 to 380 mm.
- The sea at Galle Face and Mount Lavinia is rough from roughly May to September.
- Colombo's sights, food and shopping work in every month; rain mainly changes the timing.
Colombo's climate in brief
Colombo sits on the west coast in the wet zone, a few metres above sea level. Its temperature barely changes through the year, with highs of 30 to 32 °C and nights of 24 to 26 °C. Humidity is high, usually 70 to 90 per cent, and highest in April and the monsoon months.
The rain follows the southwest monsoon and the two inter-monsoon periods. The city has a dry season from about December to March, a stormy April, a monsoon season from late May to September, and a wet October and November.
The sea off Colombo is warm, roughly 27 to 29 °C, and follows the west coast pattern: calm from about December to April and rough from about May to September. The city's beaches, at Mount Lavinia and Dehiwala, are better for a sunset walk than a long swim in any season.
- →Annual rain: roughly 2,300 to 2,400 mm.
- →Driest: January and February.
- →Wettest: May and October.
December to March
December starts with occasional storms but dries through the month, with roughly 150 to 180 mm of rain. January and February are the driest months, with roughly 60 to 100 mm each, mostly in short showers. March is dry early and stormier late, with roughly 100 to 130 mm. Days are sunny and humidity is the lowest of the year.
This is the best season for walking tours of Fort and Pettah, sunset at Galle Face Green and outdoor dining.
- →December: drying, roughly 150 to 180 mm.
- →January and February: driest, roughly 60 to 100 mm.
- →March: storms late, roughly 100 to 130 mm.
April and May
April is the hottest, most humid month, with afternoon and evening thunderstorms bringing roughly 200 to 250 mm. Mornings are usually clear. May is often the wettest month of the year, with roughly 300 to 380 mm, as the southwest monsoon sets in during the second half of the month.
Heavy storms can cause short-lived flooding on low roads, which can slow traffic to the airport. Allow extra time for airport transfers in these months.
June to September
The southwest monsoon brings showers and gusty wind. June averages roughly 180 to 250 mm, July roughly 120 to 150 mm and August roughly 100 to 130 mm, often with long sunny spells. September rises again to roughly 200 to 250 mm as afternoon storms return.
The sea at Galle Face and Mount Lavinia is rough throughout, with high waves on the seafront. The city's museums, galleries, temples and restaurants are good monsoon options, and hotels offer lower rates outside July and August.
- →June: roughly 180 to 250 mm.
- →July and August: lighter, roughly 100 to 150 mm.
- →September: storms return, roughly 200 to 250 mm.
October and November
October is one of Colombo's wettest months, with roughly 330 to 380 mm, and November follows with roughly 250 to 320 mm, most of it in the first half. Storms usually break in the afternoon or evening, often with lightning, and mornings are typically dry.
Plan outdoor sightseeing for the morning and indoor visits, such as the National Museum or shopping, for the afternoon. Lankan Stays & Trails plans Colombo days around the season, with morning walks and flexible afternoons in the wet months.
- →October: roughly 330 to 380 mm.
- →November: roughly 250 to 320 mm, drying late.
- →Mornings usually dry.
Frequently asked questions
What is the best time to visit Colombo?
January to March is the driest and most comfortable time, with sunny days and lower humidity. Colombo works in every month, though, because its museums, temples, food and shopping do not depend on the weather. Rain mainly changes the timing of outdoor visits.
What is the wettest month in Colombo?
May and October are usually the wettest months, each with roughly 300 to 380 mm of rain. May's rain comes with the southwest monsoon onset, and October's from the second inter-monsoon storms. November is also wet, especially in the first half.
What is the driest month in Colombo?
January and February are usually the driest months, with roughly 60 to 100 mm of rain each, mostly in short showers. December dries through the month and March is dry early, with storms building late in the month.
How hot is Colombo?
Colombo is hot all year, with daytime highs of about 30 to 32 °C and nights of about 24 to 26 °C. April is the hottest and most humid month. Humidity is usually 70 to 90 per cent, so it feels hotter than the thermometer suggests.
Can you swim at Galle Face or Mount Lavinia?
Galle Face is a promenade, not a swimming beach. Mount Lavinia has a beach, but its sea is rough from roughly May to September during the southwest monsoon. From December to April it is calmer, though open-water currents mean swimming should follow flags and local advice.
Does Colombo flood in the rain?
Low-lying roads can flood briefly after heavy storms, especially in April, May, October and November, because drains fill quickly. Flooding usually clears within hours. Allow extra time for airport transfers on stormy afternoons.
How does Lankan Stays & Trails plan Colombo days by season?
Colombo days are planned with walking tours and outdoor sights in the morning and indoor options, such as museums and shopping, in the afternoon during the wet months. Airport transfers are timed with extra margin when storms are likely.
Is Colombo worth visiting in the monsoon?
Yes. Colombo's museums, galleries, temples, markets and restaurants work in any weather, and showers between June and September usually pass quickly, with long bright spells in July and August. Hotels outside the July and August school holidays are often cheaper. Plan walking tours for the morning.