Negombo weather in September

In September, Negombo sees average daytime highs of 28°C and overnight lows near 26°C, with 215 mm of rain across 25.3 wet days and about 12 hours of daylight. It is the 10th-warmest and 5th-wettest month of the year here.

Day-to-day highs hold fairly steady near 28°C through the month. The sky is clear or mostly clear about 8% of the time in September, and the air most often feels miserable.

Daylight stretches from about 12 h 06 min at the start of September to 11 h 54 min by month's end. Set against the rest of the year, September is Negombo's 6th-clearest and 5th-windiest month. For the whole year in context, see Negombo's year-round climate.

Daytime high
28°
10th warmest
Overnight low
26°
6th coldest
Rainfall
215 mm
25.3 wet days
Daylight
12 hours
6:04 AM – 6:06 PM
Cloud cover
76%
6th clearest
Wind
18 km/h
5th windiest
Solar energy
5.26 kWh/m²
Travel score
3.6
out of 10

Negombo is city in Sri Lanka.

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 28°C through the month.

A typical September day in Negombo reaches about 28°C in the afternoon and slips back to 26°C overnight — a 2°C spread between the day's warmth and the night's chill. On most days the high lands between 27°C and 29°C. Set against its neighbours, September runs on par with August and on par with October.

20°23°25°28°30°151015202530
Avg high (°C)Avg low (°C)
12826
22826
32826
42826
52826
62826
72826
82826
92826
102826
112826
122826
132826
142826
152826
162826
172826
182826
192826
202826
212826
222826
232826
242826
252826
262826
272826
282826
292826
302826

How September really feels in Negombo

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.

Negombo weather by month

How September compares with the rest of the year at a glance. September is the 10th-warmest and 5th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan29° / 24°386.411.65.8
Feb30° / 25°396.511.85.5
Mar30° / 26°7615.8124.4
Apr30° / 27°1632612.23.2
May29° / 27°25428.612.33.0
Jun29° / 27°2242712.43.2
Jul28° / 26°17624.612.43.7
Aug28° / 26°16423.912.23.9
Sep28° / 26°21525.3123.6
Oct28° / 26°31426.411.83.5
Nov29° / 25°27222.411.73.8
Dec29° / 25°13714.111.65.0

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 8% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 15% of September, with mostly cloudy or overcast conditions the remaining 77%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
11981
21882
31981
42080
52080
62080
72179
82179
92377
102377
112476
122476
132476
142575
152575
162575
172476
182476
192476
202476
212377
222377
232377
242377
252278
262278
272377
282377
292377
302377

Chance of precipitation in September

Any precipitation

Negombo gets around 215 mm of rain over 25.3 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 84% and peaks near 85% on the wettest days.

0%20%40%60%80%100%151015202530
Rain chance (%)
181
281
381
482
582
683
783
883
983
1083
1184
1284
1384
1484
1584
1685
1785
1885
1985
2085
2185
2285
2385
2485
2585
2685
2785
2884
2984
3084

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, September lands in the miserable band about 87% of days. Sticky, muggy-or-worse air turns up on roughly 100% of them.

0%25%50%75%100%151015202530
Oppressive (%)Miserable (%)
11288
21288
31387
41387
51288
61288
71288
81288
91288
101288
111189
121189
131189
141189
151090
161090
171090
181090
191189
201189
211288
221387
231486
241585
251585
261684
271783
281882
291882
301981

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 19 km/h at its breeziest. It stays fairly steady from day to day.

0510152025151015202530
Wind speed (km/h)Feels
119light breeze
219light breeze
319light breeze
419light breeze
519light breeze
619light breeze
719light breeze
819light breeze
919light breeze
1019light breeze
1119light breeze
1219light breeze
1319light breeze
1419light breeze
1519light breeze
1618light breeze
1718light breeze
1818light breeze
1918light breeze
2018light breeze
2118light breeze
2218light breeze
2318light breeze
2417light breeze
2517light breeze
2617light breeze
2717light breeze
2817light breeze
2917light breeze
3016light breeze

Sunrise & sunset in September

DaylightNight

Daylight runs from about 12 h 06 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 12 minutes over September. Sunrise moves from 6:06 AM to 6:02 AM, and sunset from 6:15 PM to 5:58 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.16:066:15
212.16:066:14
312.16:066:13
412.16:066:13
512.16:066:12
612.16:056:12
712.16:056:11
812.16:056:11
912.16:056:10
1012.16:056:10
1112.16:056:09
1212.16:046:08
1312.16:046:08
1412.16:046:07
1512.06:046:07
1612.06:046:06
1712.06:046:06
1812.06:036:05
1912.06:036:04
2012.06:036:04
2112.06:036:03
2212.06:036:03
2312.06:036:02
2412.06:026:02
2512.06:026:01
2612.06:026:00
2712.06:026:00
2812.06:025:59
2912.06:025:59
3011.96:025:58

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 5.26 kWh/m².

For context, solar energy here swings from a low near 4.69 kWh/m² to a high of 6.43 kWh/m² in March across the year — September's 5.26 kWh/m² falls in the middle.

0246151015202530
Solar energy (kWh/m²)Level
15.3Bright
25.3Bright
35.3Bright
45.3Bright
55.3Bright
65.3Bright
75.3Bright
85.3Bright
95.3Bright
105.3Bright
115.3Bright
125.3Bright
135.3Bright
145.3Bright
155.3Bright
165.3Bright
175.3Bright
185.3Bright
195.3Bright
205.2Bright
215.2Bright
225.2Bright
235.2Bright
245.2Bright
255.2Bright
265.2Bright
275.2Bright
285.1Bright
295.1Bright
305.1Bright
Planning a trip in September

Hazard calendar for Negombo

In seasonPeak

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

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

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

Is September a good time to visit Negombo?

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

3.6
Sightseeing
8th-best month of the year
4.3
Beach & pool
9th-best month of the year

September is a weaker month for outdoor sightseeing in Negombo.

What to pack for Negombo in September

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

In September, Negombo sees daytime highs around 28°C and nights near 26°C. Pack light clothes and rain gear. Worth having: sun protection. About 25 days see rain.

light clothesrain gearsun protection

Sea temperature near Negombo in September

The nearest coast averages about 28°C in September — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea offshore is warmest in April at about 30°C and coldest in August 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
Jan28Warm
Feb28Tropical
Mar29Tropical
Apr30Tropical
May29Tropical
Jun28Tropical
Jul28Warm
Aug27Warm
Sep28Warm
Oct28Tropical
Nov29Tropical
Dec28Tropical

UV index in Negombo in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 13 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Negombo peaks around February 17 at about 13 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 15 at about 10 (very high).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecExtremeVery highFeb 17UV 13Dec 15UV 10
UV index (midday)Level
Jan11Extreme
Feb13Extreme
Mar12Extreme
Apr12Extreme
May12Extreme
Jun11Extreme
Jul12Extreme
Aug13Extreme
Sep13Extreme
Oct12Extreme
Nov10Extreme
Dec10Very high

Air quality in Negombo 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 Negombo is worst in March — around 30 µg/m³ PM2.5 (moderate), about 1.8× the cleanest month (August, 17 µg/m³).

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

010203040JanFebMarAprMayJunJulAugSepOctNovDecModerateMar 2030 µg/m³Aug 2417 µg/m³
PM2.5 (µg/m³)Level
Jan23Moderate
Feb23Moderate
Mar30Moderate
Apr28Moderate
May24Moderate
Jun18Moderate
Jul17Moderate
Aug17Moderate
Sep17Moderate
Oct19Moderate
Nov24Moderate
Dec23Moderate
Location & terrain

Where is Negombo?

Negombo sits at 7.2°N, 79.8°E, 8 m above sea level, in Sri Lanka. The nearest listed city is Katunayaka, 7.0 km away.

HendalaWattalaPeliyagodaKelaniya

Topography around Negombo

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

Within 3 km, the terrain around Negombo has only modest variations in elevation — a maximum elevation change of 13 m around an average of 3 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 69 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,554 m.

The land around Negombo is covered by water (52%) and artificial surfaces (28%) within 3 km, water (54%) and trees (37%) within 16 km, and trees (58%) and water (36%) within 80 km.

3 km
13 m
16 km
69 m
80 km
1,554 m
treesgrasslandcroplandartificial surfacesbare terrainwatermangroves
September weather nearby: Katunayaka 7.0 km · Ja Ela 16 km · Kandana 19 km · Welisara 21 km · Hendala 25 km · Wattala 25 km · Peliyagoda 27 km · Kelaniya 30 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 Negombo (7.2083°, 79.8358°, elevation 8 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).