Colombo (Sri Lanka) weather in December
December in Colombo: sweltering, rainy, with muggy air — a gamble, with 36°C afternoons.
Updated September 2026 · climate normals from ERA5 reanalysis
#4 of 12 months in Colombo · #887 of 1413 destinations to visit in December · comfort 64/100 (tier C)
- Days
- 31°C
- Nights
- 24°C
- Wet days
- 16
- Sun
- 9.5 h
- Humidity
- 82%
- Daylight
- 12 h

What December is like in Colombo
Dry and busy, with calm seas along the west coast and the peak fortnight at the end of the month.
peak
confidence: high
Traveller notes on Colombo in December
Regulars are specific that early in this month can still carry some of November's unsettled weather, with conditions typically clearing by mid-month - the same window where holiday-season prices also climb, a real trade-off between weather and cost. Our row backs that hot, genuinely wet read, 31C reading as a hot 36C, over 24.3C nights, with a substantial 146.6mm of rain across 16.2 days and humidity at 82 percent. Regulars are consistent this counts among the cooler, less humid stretches of the year here even though Sri Lanka stays humid year-round by most other standards. The sea sits at a warm, swimmable 28.8C regardless of which half of the month a trip lands in. The record: 9.5 hours of sun, a 12.7 kph wind and AQI 74.
Other months in Colombo
Colombo-forum threads on April weather confirm this sits right at the hottest, most humid point of the year, the stretch just before the rains properly arrive, with afternoon temperatures regularly touching mid-30s and humidity climbing alongside it. Posters describe mornings as reliably bright and sunny, showers building through the afternoon and arriving as a brief, heavy downpour rather than an all-day event, more frequent as the month wears on. Regulars are consistent the first half of April runs noticeably more comfortable than the back half, worth front-loading a Colombo stretch of a longer Sri Lanka itinerary if the schedule allows. Light, breathable clothing and frequent water breaks are called essential regardless of which half of the month a trip lands in. The record: 32.3C days feeling like a punishing 39C, 25.7C nights, a notably high 161mm across over 25 days, a 30.6C sea and 82 percent humidity.
Sri Lanka-forum threads on November weather (Colombo specifically among the destinations discussed) confirm it's the rainiest month of the year islandwide, though posters note the second half of the month usually runs better than the first. Coastal, low-lying areas like Colombo stay hot and humid enough that regulars advise against proper waterproof rain gear, an umbrella doing the job better without trapping heat against the skin. Showers, when they arrive, are heavy but limited to a few hours, and by some estimates roughly two-thirds of November days still deliver enough sunshine. Swimming on the open southwest coast is a bad bet this month, seas staying rough until at least mid-December. The record actually runs far wetter than the two-thirds-sunny framing suggests: 30.7C days feeling like a punishing 37C, 24.3C nights, a notably high 400mm across nearly 25 days, 86 percent humidity, a 29.2C sea and 8.1 hours of sun.
March is one of the two sunniest months across Sri Lanka and a good one for the west coast, and the qualification regulars add is about humidity rather than rain: this is a tropical country and it gets very humid. Our row's 31.8C reads as 38C at 77 percent. On rain they describe the inter-monsoon pattern - mostly sunny with showers possible towards the evening that do not last long - which is how 90mm spread across 15.7 precipitation days can still read as a sunny month. North of Colombo runs hot and dry; the south-west gets the occasional shower. The record: 25C nights, 10.5 hours of sun, a 29.2C sea and AQI 111.
February is the month the Colombo forum recommends without hedging - hotter and drier than the turn of the year, with sunshine most days and the southwest beaches at their best, which is why February to April is when most visitors come. The honest part of the thread is about humidity: posters put it around 70 percent by day and up to 90 percent at night, and warn that Sri Lanka gets sticky enough that you can feel it standing still. Water and repellent after dark are the standing advice; December is offered as the cooler, less humid alternative if that matters more than the sunshine. The record: 32.1C days that feel like 37C, 24.3C nights, 7.4 precipitation days, humidity 72 percent, 10.6 hours of sun, a 28C sea, AQI 110.
Add your own note from Colombo's card on the map.
Colombo climate normals — December
Monthly averages from ERA5 reanalysis. AQI is the mean US Air Quality Index for the month.
Crowds in Colombo in December
How busy the place itself is — school and mass holidays, the months an editor tagged, and how sought-after the weather makes them. Never part of the comfort score.
Peak crowdsthe editor's peak month, Year-end break in Sri Lanka, school holidays in 5 of the markets that fill it
Peak crowdsBusyShoulder seasonQuiet
Best months for Colombo's weather
Ranked by this destination's own climate comfort score across the year — a different thing from how busy it gets (see Crowds above).
Fair weatherColombo's weather peaks January–March, best around February.
Best weatherFair weatherToughest weather
What's on in Colombo in December
Recurring seasonal events, natural spectacles, closures and holidays — curated and sourced.
- Nature
Blue whales off Mirissa
1 Nov – 15 Apr · usuallyWhale seasonThe boats run out of Mirissa, three hours south, from November to April, and December to March is when the sea is calm enough to see anything. Early starts, and a genuinely rough ride on a bad morning.
Nearby, and something's on
Within 300 km of Colombo — a day trip or a short hop — with something on this month. Never part of the comfort score.
Where is Colombo?
Colombo in December — FAQ
- Is December a good time to visit Colombo?
- December in Colombo: sweltering, rainy, with muggy air — a gamble, with 36°C afternoons. It ranks #4 of 12 months for Colombo on SeasonMap's comfort score (64/100).
- What is the weather like in Colombo in December?
- In December, Colombo averages a daily high of 31°C and a low of 24.3°C, with about 146.6 mm of rain over roughly 16.2 rainy days.
- What is the air quality in Colombo in December?
- Colombo has a mean US Air Quality Index of about 74 in December.
Within 300 km: Nuwara Eliya's Adam's Peak pilgrimage season around 5 Dec – 10 May, and Mirissa's Blue whale season on 1 Nov – 15 Apr.