Trincomalee weather in September

In September, Trincomalee sees average daytime highs of 33°C and overnight lows near 26°C, with 65 mm of rain across 10.7 wet days and about 12.1 hours of daylight. It is the 5th-warmest and 6th-wettest month of the year here.

Day-to-day highs hold fairly steady near 33°C through the month. The sky is clear or mostly clear about 13% of the time in September, and the air most often feels oppressive.

Daylight stretches from about 12 h 12 min at the start of September to 11 h 54 min by month's end. Set against the rest of the year, September is Trincomalee's 8th-clearest and 4th-windiest month. For the whole year in context, see Trincomalee's year-round climate.

Daytime high
33°
5th warmest
Overnight low
26°
8th coldest
Rainfall
65 mm
10.7 wet days
Daylight
12 hours
5:58 AM – 6:01 PM
Cloud cover
73%
8th clearest
Wind
18 km/h
4th windiest
Solar energy
6 kWh/m²
Travel score
3.5
out of 10

Trincomalee is city in Sri Lanka.

Density
14,456/km²
people per km²

Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 33°C through the month.

A typical September day in Trincomalee reaches about 33°C in the afternoon and slips back to 26°C overnight — a 6°C spread between the day's warmth and the night's chill. On most days the high lands between 31°C and 34°C. Set against its neighbours, September runs on par with August and about 2°C warmer than October.

25°28°30°33°35°151015202530
Avg high (°C)Avg low (°C)
13326
23326
33326
43326
53326
63326
73326
83326
93326
103326
113326
123326
133326
143326
153326
163326
173326
183326
193326
203326
213226
223226
233226
243226
253226
263226
273226
283226
293226
303226

How September really feels in Trincomalee

Once humidity and wind are folded in, September averages 30 days that feel above 32°C and 0 that feel at or below 0°C — the comfort signal a plain temperature reading hides.

Days feeling ≥ 32°C
30
heat index over the day's high
Days feeling ≤ C
0
wind chill below the day's low

The story in September is heat — humidity pushes the afternoon "feels like" well above the raw temperature.

Trincomalee weather by month

How September compares with the rest of the year at a glance. September is the 5th-warmest and 6th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan27° / 25°12614.511.65.8
Feb28° / 25°739.711.76.3
Mar29° / 25°407.211.95.8
Apr31° / 26°561012.24.4
May33° / 27°488.212.43.6
Jun33° / 27°183.212.53.6
Jul33° / 27°315.512.43.6
Aug33° / 27°457.812.33.6
Sep33° / 26°6510.712.13.5
Oct31° / 26°18618.511.83.6
Nov28° / 25°30024.111.63.9
Dec27° / 25°27720.911.54.7

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 13% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 17% of September, with mostly cloudy or overcast conditions the remaining 70%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
12575
22575
32773
42773
52773
62872
72872
82971
92971
102971
113070
123070
133169
143268
153268
163367
173367
183367
193268
203268
213268
223169
233169
243169
253169
263070
273169
283169
293268
303268

Chance of precipitation in September

Any precipitation

Trincomalee gets around 65 mm of rain over 10.7 wet days in September. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 35% and peaks near 49% on the wettest days. The odds climb toward the end of the month.

0%20%40%60%151015202530
Rain chance (%)
128
229
329
430
530
630
730
830
930
1030
1130
1230
1330
1430
1531
1631
1732
1833
1934
2036
2137
2239
2341
2443
2544
2646
2747
2848
2949
3049

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

Most of September feels oppressive — the stacked bands show each day's mix of comfort levels, read off the dew point.

By dew point, September lands in the oppressive band about 96% of days. Sticky, muggy-or-worse air turns up on roughly 100% of them.

0%25%50%75%100%151015202530
Muggy (%)Oppressive (%)Miserable (%)
12953
22953
32953
42953
52944
62944
72944
82944
92944
102953
112953
122953
131963
141963
151963
161963
170973
180982
190982
200982
210982
220973
230973
240973
250973
260964
270964
280964
290955
300955

Wind in September

Winds average 18 km/h in September.

Across September, daily wind ranges from about 16 km/h on the calmest days to 20 km/h at its breeziest. It stays fairly steady from day to day.

0510152025151015202530
Wind speed (km/h)Feels
120light breeze
220light breeze
320light breeze
420light breeze
520light breeze
619light breeze
719light breeze
819light breeze
919light breeze
1019light breeze
1119light breeze
1219light breeze
1319light breeze
1419light breeze
1519light breeze
1619light breeze
1719light breeze
1819light breeze
1918light breeze
2018light breeze
2118light breeze
2218light breeze
2317light breeze
2417light breeze
2517light breeze
2617light breeze
2717light breeze
2816light breeze
2916light breeze
3016light breeze

Sunrise & sunset in September

DaylightNight

Daylight runs from about 12 h 12 min at the start of September to 11 h 54 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 18 minutes over September. Sunrise moves from 6:00 AM to 5:56 AM, and sunset from 6:10 PM to 5:52 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.26:006:10
212.26:006:09
312.26:006:09
412.15:596:08
512.15:596:07
612.15:596:07
712.15:596:06
812.15:596:06
912.15:596:05
1012.15:596:04
1112.15:596:04
1212.15:596:03
1312.15:586:03
1412.15:586:02
1512.15:586:01
1612.05:586:01
1712.05:586:00
1812.05:586:00
1912.05:585:59
2012.05:575:58
2112.05:575:58
2212.05:575:57
2312.05:575:57
2412.05:575:56
2512.05:575:55
2612.05:575:55
2712.05:575:54
2811.95:575:54
2911.95:565:53
3011.95:565:52

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 6 kWh/m².

For context, solar energy here swings from a low near 4.16 kWh/m² to a high of 6.51 kWh/m² in March across the year — September's 6 kWh/m² falls in the middle.

0246151015202530
Solar energy (kWh/m²)Level
16.0Intense
26.0Intense
36.0Intense
46.0Intense
56.0Intense
66.0Intense
76.0Intense
86.0Intense
96.0Intense
106.0Intense
116.0Intense
126.0Intense
136.0Intense
146.0Intense
156.0Intense
166.0Intense
176.0Intense
186.0Intense
196.0Intense
206.0Intense
216.0Bright
226.0Bright
236.0Bright
245.9Bright
255.9Bright
265.9Bright
275.9Bright
285.9Bright
295.8Bright
305.8Bright
Planning a trip in September

Hazard calendar for Trincomalee

In seasonPeak

In September, Trincomalee sits inside its cyclone season. The full year is below, with each hazard's peak months called out.

Trincomalee sits in the North Indian Ocean cyclone zone; the season peaks May and October–November.

Trincomalee's monsoon runs October–December, when most of the year's rain falls.

Cyclone
Monsoon
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Is September a good time to visit Trincomalee?

Our two travel scores rate September for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal).

3.5
Sightseeing
12th-best month of the year
6.0
Beach & pool
8th-best month of the year

September is a weaker month for outdoor sightseeing in Trincomalee.

What to pack for Trincomalee in September

From September's temperature range, rain chance, sun and wind — what's worth putting in the bag.

In September, Trincomalee sees daytime highs around 33°C and nights near 26°C. Pack light clothes and sun protection. Worth having: rain gear. About 11 days see rain.

light clothessun protectionrain gear

Sea temperature near Trincomalee in September

The nearest coast averages about 29°C in September — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea at the nearest coast (about 17 km away) is warmest in May at about 30°C and coldest in January near 27°C.

The water stays above 20°C all year — warm enough for a swim any month.

26°28°30°32°JanFebMarAprMayJunJulAugSepOctNovDecwarmtropicalcomfortable to swim
Sea temperature (°C)Comfort
Jan27Warm
Feb28Warm
Mar29Tropical
Apr30Tropical
May30Tropical
Jun30Tropical
Jul29Tropical
Aug29Tropical
Sep29Tropical
Oct29Tropical
Nov29Tropical
Dec28Warm

UV index in Trincomalee in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 12 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Trincomalee peaks around May 10 at about 13 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 20 at about 9 (very high).

The index reaches 3 or more — the level where the WHO recommends sun protection — every month of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecExtremeVery highMay 10UV 13Dec 20UV 9
UV index (midday)Level
Jan10Very high
Feb12Extreme
Mar13Extreme
Apr13Extreme
May14Extreme
Jun11Extreme
Jul11Extreme
Aug13Extreme
Sep12Extreme
Oct13Extreme
Nov11Extreme
Dec9Very high

Air quality in Trincomalee in September

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see where September falls, not just the annual average.

Air quality in Trincomalee is worst in May — around 28 µg/m³ PM2.5 (moderate), and holds fairly steady the rest of the year.

Modeled monthly averages (CAMS reanalysis, 2015–2024).

0102030JanFebMarAprMayJunJulAugSepOctNovDecModerateMay 1028 µg/m³Jul 2120 µg/m³
PM2.5 (µg/m³)Level
Jan22Moderate
Feb21Moderate
Mar24Moderate
Apr27Moderate
May28Moderate
Jun21Moderate
Jul20Moderate
Aug20Moderate
Sep21Moderate
Oct25Moderate
Nov24Moderate
Dec22Moderate
Location & terrain

Where is Trincomalee?

Trincomalee sits at 8.6°N, 81.2°E, 10 m above sea level, in Sri Lanka. The nearest listed city is Vakarai, 54 km away.

VakaraiPolonnaruwaVavuniyaSigiriyaMullaittivuAnuradhapuraEravur TownDambulla

Topography around Trincomalee

How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Trincomalee.

Within 3 km, the terrain around Trincomalee has only modest variations in elevation — a maximum elevation change of 78 m around an average of 5 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 161 m; within 80 km, large variations in elevation — a maximum elevation change of 684 m.

The land around Trincomalee is covered by water (62%) within 3 km, water (55%) and trees (24%) within 16 km, and trees (41%) and water (38%) within 80 km.

3 km
78 m
16 km
161 m
80 km
684 m
treesgrasslandcroplandartificial surfacesbare terrainwatermangroves
September weather nearby: Vakarai 54 km · Polonnaruwa 75 km · Vavuniya 83 km · Sigiriya 87 km · Mullaittivu 89 km · Anuradhapura 94 km · Eravur Town 98 km · Dambulla 102 km

Sri Lanka travel facts

Travel advisory
Level 2
Exercise Increased Caution
Power plugs
Type D / G / M
230 V · 50 Hz
Prices
≈ 27% of US
price level, 2025
GDP per capita
$5,002
2025
Happiness
4.0 / 10
World Happiness, 2025
Safe drinking water
47%
of population, 2024
Homicide rate
3.3
per 100k, 2019
Road deaths
19.7
per 100k/yr, 2019
Income group
Upper middle
World Bank
English
Low
EF EPI 486
Religion
Buddhist 70%Hindu 13%Muslim 10%Roman Catholic 6%

Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.

Data sources

Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for Trincomalee (8.5778°, 81.2289°, elevation 10 m), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google. Tropical-cyclone seasons are the published climatological basin seasons (NOAA National Hurricane Center / regional warning centres). Sea temperatures are the NOAA OISST v2.1 1991–2020 monthly climatology (public domain), sampled at the nearest ocean point. UV index is derived from CAMS (Copernicus Atmosphere Monitoring Service) clear-sky UV data — contains modified Copernicus Atmosphere Monitoring Service information. Monthly air-quality (PM2.5) seasonality is from the CAMS EAC4 reanalysis (Copernicus Atmosphere Monitoring Service), scaled to the WHO annual mean where available. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).