SeasonMapTrincomalee weather in September
Sri Lanka
September in Trincomalee: sweltering, a little rain, with clean air — fine if you can take 37°C afternoons.
#6 of 12 months in Trincomalee · #503 of 1383 destinations to visit in September · comfort 85/100 (tier A)
Updated September 2026 · climate normals from ERA5 reanalysis
Traveller notes on Trincomalee in September
Other months in Trincomalee
Trincomalee's forum calls March dry season on land, but flags the sea as the catch — one visitor was told by hotel staff not to go in past their knees until late April or May, when the rougher swell finally settles. Another had a genuinely sunny, trouble-free stay in mid-March, sea aside.
Add your own note from Trincomalee's card on the map.
Trincomalee climate normals — September
| Daytime high | 34°C / 92°F | 🔥 sweltering |
|---|---|---|
| Nighttime low | 25°C / 77°F | |
| Feels like (high) | 37°C / 99°F | |
| Sea temperature | 28°C / 83°F | ♨️ bath-warm |
| Rainfall | 47 mm / 1.9 in | 🌦 some rain |
| Rainy days | 9 days | |
| Humidity | 70% | 💧 humid |
| Dew point | 24°C / 74°F | |
| Sunshine | 10.3 h/day | |
| Daylight | 12.2 h | |
| Wind | 25 km/h / 15 mph | |
| Air quality (US AQI) | 29 | 🍃 good |
Monthly averages from ERA5 reanalysis. AQI is the mean US Air Quality Index for the month.
Crowds in Trincomalee in September
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 crowdsEast coast season, August break in Sri Lanka, school holidays in 3 of the markets that fill it(estimated)
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).
Fair weatherTrincomalee's best weather comes in February, March and June — separate windows, not one continuous season.
Best weatherFair weatherToughest weather
What's on in Trincomalee in September
Recurring seasonal events, natural spectacles, closures and holidays — curated and sourced.
- Rule
Pigeon Island park rules
1 Jan – 31 DecClosuresThe 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
East coast season
1 May – 30 SepDry seasonCrowdedThe mirror image of the south: while Galle and Mirissa are shut in for the monsoon, Nilaveli and Uppuveli are flat, clear and open. Sri Lanka's summer answer to a washed-out southwest.
- Nature
Blue and sperm whale season
1 May – 15 Oct · usuallyThe shelf drops away close to shore here, so the boats reach the whales in under an hour rather than two. Sperm whale pods as well as blues, with June to August the reliable stretch.
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?
Trincomalee in September — FAQ
- Is September a good time to visit Trincomalee?
- September in Trincomalee: sweltering, a little rain, with clean air — fine if you can take 37°C afternoons. It ranks #6 of 12 months for Trincomalee on SeasonMap's comfort score (85/100).
- What is the weather like in Trincomalee in September?
- In September, Trincomalee averages a daily high of 33.5°C and a low of 25°C, with about 47.3 mm of rain over roughly 9.2 rainy days.
- What is the air quality in Trincomalee in September?
- Trincomalee has a mean US Air Quality Index of about 29 in September.
Other months in Trincomalee
Compare Trincomalee in September
Warmer or cooler than Trincomalee in September
Similar destinations in South Asia — September
Within 300 km: Sigiriya's The Gathering at Minneriya around 15 Jul – 30 Sep, and Colombo's East coast season around 1 May – 30 Sep.