Dehiwala-Mount Lavinia weather in December

In December, Dehiwala-Mount Lavinia sees average daytime highs of 29°C and overnight lows near 25°C, with 175 mm of rain across 16.7 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 Dehiwala-Mount Lavinia's 5th-clearest and 7th-windiest month. For the whole year in context, see Dehiwala-Mount Lavinia's year-round climate.

Daytime high
29°
6th warmest
Overnight low
25°
2nd coldest
Rainfall
175 mm
16.7 wet days
Daylight
11 h 36 min
6:19 AM – 5:55 PM
Cloud cover
68%
5th clearest
Wind
14 km/h
7th windiest
Solar energy
4.82 kWh/m²
Travel score
4.6
out of 10

Dehiwala-Mount Lavinia is suburb of Colombo, Western Province, 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 Dehiwala-Mount Lavinia 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 28°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
202925
212925
222925
232925
242925
252925
262925
272925
282925
292925
302925
312925

How December really feels in Dehiwala-Mount Lavinia

Once humidity and wind are folded in, December averages 23 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
23
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.

Dehiwala-Mount Lavinia 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° / 25°608.811.65.4
Feb30° / 25°578.511.85.2
Mar30° / 26°7514.9124.5
Apr30° / 26°17424.412.13.3
May29° / 27°2932912.33.0
Jun29° / 26°25726.512.43.3
Jul28° / 26°20525.312.43.7
Aug28° / 26°18324.612.23.8
Sep28° / 26°23224.3123.7
Oct28° / 25°3282611.83.6
Nov29° / 25°33023.811.73.7
Dec29° / 25°17516.711.64.6

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 16% of December, with mostly cloudy or overcast conditions the remaining 62%. Skies tend to open up as the month goes on.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
12971
23070
33070
43169
53268
63268
73268
83268
93268
103268
113367
123367
133367
143466
153565
163565
173664
183664
193862
203961
214060
224159
234258
244456
254555
264654
274753
284852
294951
305050
315149

Chance of precipitation in December

Any precipitation

Dehiwala-Mount Lavinia gets around 175 mm of rain over 16.7 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 54% and peaks near 65% on the wettest days. The odds ease toward the end of the month.

0%20%40%60%80%151015202531
Rain chance (%)
165
264
363
462
561
661
760
860
960
1060
1160
1259
1359
1459
1558
1658
1757
1856
1955
2053
2152
2250
2348
2446
2545
2643
2741
2840
2938
3037
3136

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 (%)
1067717
2067816
3077716
4077716
5087715
6087715
7087715
8097615
9097714
10097714
11097714
12097813
13097813
140107812
150107812
160107911
170117910
180117910
19112789
20113788
21114778
22115777
23116767
24117766
25118756
26119746
27120745
28121735
29222715
30223714
31223714

Wind in December

Winds average 14 km/h in December.

Across December, daily wind ranges from about 12 km/h on the calmest days to 15 km/h at its breeziest. It stays fairly steady from day to day.

05101520151015202531
Wind speed (km/h)Feels
112calm
212calm
312light breeze
412light breeze
512light breeze
613light breeze
713light breeze
813light breeze
913light breeze
1013light breeze
1113light breeze
1213light breeze
1314light breeze
1414light breeze
1514light breeze
1614light breeze
1714light breeze
1814light breeze
1914light breeze
2014light breeze
2114light breeze
2215light breeze
2315light breeze
2415light breeze
2515light breeze
2615light breeze
2715light breeze
2815light breeze
2915light breeze
3015light breeze
3115light 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 6:11 AM to 6:25 AM, and sunset from 5:49 PM to 6:02 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
111.66:115:49
211.66:125:50
311.66:125:50
411.66:135:50
511.66:135:50
611.66:145:51
711.66:145:51
811.66:155:52
911.66:155:52
1011.66:165:52
1111.66:165:53
1211.66:175:53
1311.66:175:54
1411.66:185:54
1511.66:185:54
1611.66:195:55
1711.66:195:55
1811.66:205:56
1911.66:205:56
2011.66:205:57
2111.66:215:57
2211.66:215:58
2311.66:225:58
2411.66:225:59
2511.66:235:59
2611.66:235:59
2711.66:246:00
2811.66:246:00
2911.66:256:01
3011.66:256:01
3111.66:256:02

Solar energy in December

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in December, about 4.82 kWh/m².

For context, solar energy here swings from a low near 4.62 kWh/m² to a high of 6.26 kWh/m² in March across the year — December's 4.82 kWh/m² sits near the bottom.

0246151015202531
Solar energy (kWh/m²)Level
14.7Bright
24.7Bright
34.7Bright
44.7Bright
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 Dehiwala-Mount Lavinia

In seasonPeak

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

Dehiwala-Mount Lavinia 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 Dehiwala-Mount Lavinia?

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

4.6
Sightseeing
3rd-best month of the year
5.9
Beach & pool
4th-best month of the year

December is a reasonable time to visit Dehiwala-Mount Lavinia for sightseeing.

What to pack for Dehiwala-Mount Lavinia in December

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

In December, Dehiwala-Mount Lavinia sees daytime highs around 29°C and nights near 25°C. Pack light clothes and rain gear. Worth having: sun protection. About 17 days see rain.

light clothesrain gearsun protection

Sea temperature near Dehiwala-Mount Lavinia 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 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 Dehiwala-Mount Lavinia in December

LowModerateHighVery highExtreme

Clear-sky midday UV in December peaks around 10 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Dehiwala-Mount Lavinia peaks around September 10 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 highSep 10UV 13Dec 15UV 10
UV index (midday)Level
Jan10Extreme
Feb12Extreme
Mar12Extreme
Apr12Extreme
May12Extreme
Jun11Extreme
Jul11Extreme
Aug13Extreme
Sep13Extreme
Oct12Extreme
Nov10Extreme
Dec10Very high

Air quality in Dehiwala-Mount Lavinia 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 Dehiwala-Mount Lavinia is worst in February — around 37 µg/m³ PM2.5 (poor), about 2.1× the cleanest month (September, 18 µg/m³).

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

010203040JanFebMarAprMayJunJulAugSepOctNovDecPoorModerateFeb 1437 µg/m³Sep 1118 µg/m³
PM2.5 (µg/m³)Level
Jan36Poor
Feb37Poor
Mar36Poor
Apr28Moderate
May24Moderate
Jun19Moderate
Jul18Moderate
Aug18Moderate
Sep18Moderate
Oct20Moderate
Nov30Moderate
Dec34Moderate
Location & terrain

Where is Dehiwala-Mount Lavinia?

Dehiwala-Mount Lavinia sits at 6.8°N, 79.9°E, 16 m above sea level, in Sri Lanka. The nearest listed city is Maharagama, 6.0 km away.

Topography around Dehiwala-Mount Lavinia

How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Dehiwala-Mount Lavinia.

Within 3 km, the terrain around Dehiwala-Mount Lavinia has only modest variations in elevation — a maximum elevation change of 33 m around an average of 7 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 74 m; within 80 km, very significant variations in elevation — a maximum elevation change of 2,145 m.

The land around Dehiwala-Mount Lavinia is covered by artificial surfaces (51%) and water (32%) within 3 km, water (50%), trees (25%) and artificial surfaces (21%) within 16 km, and trees (59%) and water (37%) within 80 km.

3 km
33 m
16 km
74 m
80 km
2,145 m
treesgrasslandcroplandartificial surfacesbare terrainwater
December weather nearby: Maharagama 6.0 km · Sri Jayewardenepura Kotte 6.0 km · Pita Kotte 7.0 km · Moratuwa 8.0 km · Battaramulla South 8.0 km · Kolonnawa 10 km · Kotikawatta 11 km · Colombo 11 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 Dehiwala-Mount Lavinia (6.8402°, 79.8712°, elevation 16 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).