Chilaw weather in December

In December, Chilaw sees average daytime highs of 29°C and overnight lows near 25°C, with 131 mm of rain across 13.5 wet days and about 11.6 hours of daylight. It is the 6th-warmest and 8th-wettest month of the year here.

Day-to-day highs hold fairly steady near 29°C through the month. The sky is clear or mostly clear about 21% of the time in December, and the air most often feels oppressive.

Daylight stretches from about 11 h 36 min at the start of December to 11 h 36 min by month's end. Set against the rest of the year, December is Chilaw's 5th-clearest and 7th-windiest month. For the whole year in context, see Chilaw's year-round climate.

Daytime high
29°
6th warmest
Overnight low
25°
3rd coldest
Rainfall
131 mm
13.5 wet days
Daylight
11 h 36 min
6:20 AM – 5:54 PM
Cloud cover
68%
5th clearest
Wind
17 km/h
7th windiest
Solar energy
4.83 kWh/m²
Travel score
5.0
out of 10

Chilaw is large town in Puttalam district, Sri Lanka.

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

Temperature in December

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 29°C through the month.

A typical December day in Chilaw reaches about 29°C in the afternoon and slips back to 25°C overnight — a 4°C spread between the day's warmth and the night's chill. On most days the high lands between 27°C and 30°C. Set against its neighbours, December runs on par with November and on par with January.

20°25°30°35°151015202531
Avg high (°C)Avg low (°C)
12925
22925
32925
42925
52925
62925
72925
82925
92925
102925
112925
122925
132925
142925
152925
162925
172925
182925
192925
202924
212924
222924
232924
242924
252924
262924
272924
282924
292924
302924
312924

How December really feels in Chilaw

Once humidity and wind are folded in, December averages 24 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
24
heat index over the day's high
Days feeling ≤ C
0
wind chill below the day's low

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

Chilaw weather by month

How December compares with the rest of the year at a glance. December is the 6th-warmest and 8th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan30° / 24°376.111.65.7
Feb31° / 25°33611.85.2
Mar31° / 26°6913.711.94.4
Apr30° / 26°15224.912.23.2
May30° / 27°22128.112.33.0
Jun29° / 27°18525.812.43.4
Jul28° / 26°13322.112.44.0
Aug28° / 26°12921.912.24.1
Sep28° / 26°18024.4123.7
Oct29° / 26°29826.111.83.5
Nov29° / 25°26122.211.73.8
Dec29° / 25°13113.511.65.0

Cloud cover in December

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 21% of the time in December.

Beyond those clear spells, partly cloudy skies cover about 14% of December, with mostly cloudy or overcast conditions the remaining 65%. Skies tend to open up as the month goes on.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
12872
22971
33070
43070
53070
63070
73070
83070
93070
103070
113070
123169
133169
143169
153268
163268
173268
183268
193466
203466
213565
223763
233862
243961
254159
264258
274456
284555
294654
304852
314951

Chance of precipitation in December

Any precipitation

Chilaw gets around 131 mm of rain over 13.5 wet days in December. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 43% and peaks near 57% on the wettest days. The odds ease toward the end of the month.

0%20%40%60%151015202531
Rain chance (%)
157
255
354
453
552
651
750
849
949
1048
1147
1247
1346
1446
1546
1645
1745
1844
1943
2042
2141
2240
2339
2437
2536
2634
2733
2831
2930
3029
3128

Humidity in December

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, December lands in the oppressive band about 76% of days. Sticky, muggy-or-worse air turns up on roughly 100% of them.

0%25%50%75%100%151015202531
Humid (%)Muggy (%)Oppressive (%)Miserable (%)
1077716
2077815
3087715
4087715
5097615
6097615
70107614
80107614
90107614
100107614
110107713
120107713
130107713
140117712
150117712
160117811
170127810
18012799
19013789
20014788
21014797
22015787
23116776
24117766
25118765
26119755
27121744
28121744
29122734
30123724
31224713

Wind in December

Winds average 17 km/h in December.

Across December, daily wind ranges from about 15 km/h on the calmest days to 19 km/h at its breeziest. It stays fairly steady from day to day.

0510152025151015202531
Wind speed (km/h)Feels
115light breeze
215light breeze
315light breeze
415light breeze
515light breeze
616light breeze
716light breeze
816light breeze
916light breeze
1016light breeze
1116light breeze
1216light breeze
1317light breeze
1417light breeze
1517light breeze
1617light breeze
1717light breeze
1817light breeze
1918light breeze
2018light breeze
2118light breeze
2218light breeze
2318light breeze
2418light breeze
2518light breeze
2618light breeze
2718light breeze
2818light breeze
2918light breeze
3018light breeze
3119light breeze

Sunrise & sunset in December

DaylightNight

Daylight runs from about 11 h 36 min at the start of December to 11 h 36 min by month's end. The lit band spans sunrise to sunset each day.

Days grow by about 0 minutes over December. Sunrise moves from 6:13 AM to 6:27 AM, and sunset from 5:48 PM to 6:01 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
111.66:135:48
211.66:135:49
311.66:145:49
411.66:145:49
511.66:155:50
611.66:155:50
711.66:165:50
811.66:165:51
911.66:175:51
1011.66:175:51
1111.66:185:52
1211.66:185:52
1311.66:195:53
1411.66:195:53
1511.66:205:53
1611.66:205:54
1711.66:215:54
1811.66:215:55
1911.66:225:55
2011.66:225:56
2111.66:235:56
2211.66:235:57
2311.66:235:57
2411.66:245:58
2511.66:245:58
2611.66:255:58
2711.66:255:59
2811.66:265:59
2911.66:266:00
3011.66:276:00
3111.66:276:01

Solar energy in December

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in December, about 4.83 kWh/m².

For context, solar energy here swings from a low near 4.7 kWh/m² to a high of 6.51 kWh/m² in March across the year — December's 4.83 kWh/m² sits near the bottom.

0246151015202531
Solar energy (kWh/m²)Level
14.7Bright
24.8Bright
34.8Bright
44.8Bright
54.8Bright
64.8Bright
74.8Bright
84.8Bright
94.8Bright
104.8Bright
114.8Bright
124.8Bright
134.8Bright
144.8Bright
154.8Bright
164.8Bright
174.8Bright
184.8Bright
194.8Bright
204.8Bright
214.8Bright
224.8Bright
234.9Bright
244.9Bright
254.9Bright
265.0Bright
275.0Bright
285.0Bright
295.1Bright
305.1Bright
315.1Bright
Planning a trip in December

Hazard calendar for Chilaw

In seasonPeak

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

Chilaw 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 December a good time to visit Chilaw?

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

5.0
Sightseeing
3rd-best month of the year
6.3
Beach & pool
3rd-best month of the year

December is a reasonable time to visit Chilaw for sightseeing. The water and warmth also suit a beach or pool day.

What to pack for Chilaw in December

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

In December, Chilaw sees daytime highs around 29°C and nights near 25°C. Pack light clothes. Worth having: rain gear and sun protection. About 14 days see rain.

light clothesrain gearsun protection

Sea temperature near Chilaw in December

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

The sea at the nearest coast (about 20 km away) 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
Feb28Warm
Mar29Tropical
Apr30Tropical
May29Tropical
Jun28Tropical
Jul27Warm
Aug27Warm
Sep28Warm
Oct28Tropical
Nov29Tropical
Dec28Tropical

UV index in Chilaw in December

LowModerateHighVery highExtreme

Clear-sky midday UV in December peaks around 9 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Chilaw peaks around April 18 at about 13 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 19 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 highApr 18UV 13Dec 19UV 9
UV index (midday)Level
Jan10Very high
Feb13Extreme
Mar13Extreme
Apr13Extreme
May13Extreme
Jun11Extreme
Jul12Extreme
Aug13Extreme
Sep13Extreme
Oct12Extreme
Nov10Extreme
Dec9Very high

Air quality in Chilaw in December

GoodModeratePoorUnhealthyVery unhealthy

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

Air quality in Chilaw 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 Chilaw?

Chilaw sits at 7.6°N, 79.8°E, 8 m above sea level, in Sri Lanka. The nearest listed city is Negombo, 41 km away.

NegomboKatunayakaPuttalamJa ElaKandanaWelisaraKurunegalaHendala

Topography around Chilaw

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

Within 3 km, the terrain around Chilaw has only modest variations in elevation — a maximum elevation change of 15 m around an average of 3 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 67 m; within 80 km, large variations in elevation — a maximum elevation change of 977 m.

The land around Chilaw is covered by water (38%) and trees (33%) within 3 km, water (52%) and trees (39%) within 16 km, and trees (53%) and water (37%) within 80 km.

3 km
15 m
16 km
67 m
80 km
977 m
treesgrasslandcroplandartificial surfacesbare terrainwaterwetlandmangroves
December weather nearby: Negombo 41 km · Katunayaka 46 km · Puttalam 51 km · Ja Ela 57 km · Kandana 60 km · Welisara 62 km · Kurunegala 64 km · Hendala 66 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 Chilaw (7.5758°, 79.7953°, 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).