Trincomalee weather in December

December in Trincomalee: hot, soaked, with clean air — fine if you can take 21 rainy days.

Updated September 2026 · climate normals from ERA5 reanalysis

Trincomalee🇱🇰 Sri Lanka · Sri Lanka & the Maldives · Beach68
  1. 77Jan
  2. 87Feb
  3. 90Mar
  4. 86Apr
  5. 80May
  6. 89Jun
  7. 87Jul
  8. 84Aug
  9. 85Sep
  10. 71Oct
  11. 59Nov
  12. 68Dec

#11 of 12 months in Trincomalee · #793 of 1413 destinations to visit in December · comfort 68/100 (tier C)

Days
29°C
Nights
24°C
Wet days
21
Sun
9.2 h
Humidity
83%
Daylight
12 h
Trincomalee, Sri Lanka
Photo: Sachith Ravishka Kodikara · Pexels

Traveller notes on Trincomalee in December

Other months in Trincomalee

Regulars are specific this counts as peak season on the east coast precisely because the southwest monsoon, running May through September, hits the south and west coasts instead, leaving conditions here calm and genuinely good for snorkeling and swimming. Our row backs that hot, genuinely dry read, 34C reading as a scorching 38C, over 25.5C nights feeling 27C, with rain light at 47.8mm across 8.7 days and humidity at 70 percent. Regulars are consistent the typical pattern is sunny days with just an odd late-afternoon or evening shower rather than a disruptive wet day, tanning, swimming, snorkeling and scuba all in their element. The sea sits at a bath-warm 28.5C. The record: 10.4 hours of sun, a 25.2 kph wind and AQI 40.
EastCoastCalmWhileMonsoonHitsWest · August · 1 month ago · Read more on Tripadvisor ↗
Regulars describe this coast's dry season as just beginning, with conditions turning sunnier by the day even though the sea itself hasn't fully settled - one visitor specifically notes the water here isn't yet calm this month, a genuine mismatch between improving land weather and still-rough surf. Our row backs the building heat and dryness, 33.5C reading as a hot 40C at 76 percent humidity, over 25.6C nights, with 49.2mm of rain across 10 days. Regulars call the trade for the rougher sea a genuinely quiet beach experience, with one describing miles of empty sand and good surf for those who want it rather than calm swimming. The sea holds a warm 30.1C regardless of the chop. The record: 11 hours of sun, a 16.6 kph wind and AQI 41.
DrySeasonStartingButSeaNotCalmYet · April · 1 month ago · Read more on Tripadvisor ↗
July is the month Sri Lanka splits in two, and this is the good half. The south-west monsoon is working the other side of the island, so regulars send July visitors here - Trincomalee, Nilaveli, Uppuveli, Pasikuda - and the reason they give is sea state rather than sunshine: these beaches are calm and swimmable while the south coast is rough. Our row backs the dry claim at 35.8mm across 6.9 days with 10.3 hours of sun. It also names the cost of being on the dry side of a monsoon: 34.2C reading as 38C, the hottest daytime figure in this batch, over nights that only fall to 25.8C. The record: humidity 68 percent, a 25.8 kph wind, a 28.9C sea and AQI 29.
TheOtherCoastIsHavingItsMonsoon · July · 1 month ago · Read more on Tripadvisor ↗
Sri Lanka's two coasts run opposite seasons and February belongs to the other one. Regulars say Trinco is out of season now, with high waves, because the rain reaches the island from the north-east in this period - so the advice is to avoid the eastern shore, Trincomalee, Pasikudah and Arugam Bay, and take the south-west instead. Our row's 69mm across 10.5 days looks mild on paper, but the sea state rather than the rainfall is the issue. Whales follow the same split: Mirissa's blue whale season runs December to April while Trincomalee's is March to August, when the strike rate here passes eighty percent. Come in July, not February. The record: 29.7C over 24.7C reading as 34C, humidity 77 percent, a 27.2C sea and AQI 57.
WrongCoastThisMonth · February · 1 month ago · Read more on Tripadvisor ↗

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Trincomalee climate normals — December

Daytime high29°C / 84°F🥵 hot
Nighttime low24°C / 76°F
Feels like (high)33°C / 91°F
Sea temperature28°C / 82°F♨️ bath-warm
Rainfall243 mm / 9.6 in⛈ soaked
Rainy days21 days
Humidity83%💦 very humid
Dew point24°C / 75°F
Sunshine9.2 h/day
Daylight11.6 h
Wind19 km/h / 12 mph
Air quality (US AQI)43🍃 good

Monthly averages from ERA5 reanalysis. AQI is the mean US Air Quality Index for the month.

Crowds in Trincomalee 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.

BusyYear-end break in Sri Lanka, school holidays in 5 of the markets that fill it(estimated)

JFMAMJJASOND

Peak crowdsBusyShoulder seasonQuiet

Best months for Trincomalee'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).

Toughest weatherTrincomalee's best weather comes in February, March and June — separate windows, not one continuous season.

December coincides with Cyclone season.

JFMAMJJASOND

Best weatherFair weatherToughest weather

What's on in Trincomalee in December

Recurring seasonal events, natural spectacles, closures and holidays — curated and sourced.

  • Rule

    Pigeon Island park rules

    1 Jan – 31 DecClosures

    The island is a national park with a wildlife-department ticket bought at the Nilaveli jetty, a cap on visitor numbers and a ban on standing on the reef. Boats do not run when the sea is up. Source ↗

  • Season

    Northeast (Maha) monsoon

    1 Nov – 15 Feb · usuallyRiskClosures

    The east coast's wet season, and a real shutdown: whale boats stop, the Pigeon Island crossing is off most days, and the beach hotels at Nilaveli close or drop to a caretaker.

  • Hazard

    Cyclone season

    1 Nov – 31 Dec · usuallyClosures

    The east coast faces the storms the Bay of Bengal sends west late in the year: Burevi crossed just north of town in 2020 and Ditwah flooded the district in 2025. Boats to Pigeon Island stop and the coast road can go under. Source ↗

  • Season

    Wet season

    MonsoonRisk

    21 rainy days and about 243 mm in the month — the real kind of rainy season, not afternoon showers.

    from the climate normals

What's on around the world in December →

Nearby, and something's on

Within 300 km of Trincomalee — a day trip or a short hop — with something on this month. Never part of the comfort score.

Where is Trincomalee?

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Trincomalee in December — FAQ

Is December a good time to visit Trincomalee?
December in Trincomalee: hot, soaked, with clean air — fine if you can take 21 rainy days. It ranks #11 of 12 months for Trincomalee on SeasonMap's comfort score (68/100).
What is the weather like in Trincomalee in December?
In December, Trincomalee averages a daily high of 29.1°C and a low of 24.3°C, with about 243.4 mm of rain over roughly 21.1 rainy days.
What is the air quality in Trincomalee in December?
Trincomalee has a mean US Air Quality Index of about 43 in December.

Within 300 km: Nuwara Eliya's Adam's Peak pilgrimage season around 5 Dec – 10 May, and Colombo's Blue whales off Mirissa around 1 Nov – 15 Apr.