Dehiwala-Mount Lavinia weather in May

In May, Dehiwala-Mount Lavinia sees average daytime highs of 29°C and overnight lows near 27°C, with 293 mm of rain across 29 wet days and about 12.3 hours of daylight. It is the 5th-warmest and 3rd-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 5% of the time in May, and the air most often feels miserable.

Daylight stretches from about 12 h 12 min at the start of May to 12 h 24 min by month's end. Set against the rest of the year, May is Dehiwala-Mount Lavinia's 8th-clearest and 5th-windiest month. For the whole year in context, see Dehiwala-Mount Lavinia's year-round climate.

Daytime high
29°
5th warmest
Overnight low
27°
12th coldest
Rainfall
293 mm
29 wet days
Daylight
12 h 18 min
5:57 AM – 6:16 PM
Cloud cover
79%
8th clearest
Wind
17 km/h
5th windiest
Solar energy
4.89 kWh/m²
Travel score
3.0
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 May

Average highAverage lowShaded bands: 10–90% of days

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

A typical May day in Dehiwala-Mount Lavinia reaches about 29°C in the afternoon and slips back to 27°C overnight — a 3°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, May runs on par with April and on par with June.

25°28°30°33°35°151015202531
Avg high (°C)Avg low (°C)
13027
23027
33027
43027
53027
63027
73027
83027
93027
103027
113027
122927
132927
142927
152927
162927
172927
182927
192927
202927
212927
222927
232927
242927
252927
262926
272926
282926
292926
302926
312926

How May really feels in Dehiwala-Mount Lavinia

Once humidity and wind are folded in, May averages 31 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
31
heat index over the day's high
Days feeling ≤ C
0
wind chill below the day's low

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

Dehiwala-Mount Lavinia weather by month

How May compares with the rest of the year at a glance. May is the 5th-warmest and 3rd-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 May

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 5% of the time in May.

Beyond those clear spells, partly cloudy skies cover about 17% of May, with mostly cloudy or overcast conditions the remaining 78%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
12872
22872
32872
42773
52773
62674
72674
82575
92575
102575
112575
122476
132476
142476
152476
162377
172377
182278
192179
202179
212080
221981
231981
241882
251882
261783
271684
281585
291585
301486
311486

Chance of precipitation in May

Any precipitation

Dehiwala-Mount Lavinia gets around 293 mm of rain over 29 wet days in May. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 93% and peaks near 95% on the wettest days.

0%20%40%60%80%100%151015202531
Rain chance (%)
191
291
391
491
591
692
792
892
992
1093
1193
1293
1393
1493
1594
1694
1794
1894
1994
2094
2195
2295
2395
2495
2595
2695
2795
2895
2995
3095
3195

Humidity in May

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, May lands in the miserable band about 99% of days. Sticky, muggy-or-worse air turns up on roughly 100% of them.

0%25%50%75%100%151015202531
Oppressive (%)Miserable (%)
1397
2298
3298
4298
5298
6298
7199
8199
9199
10199
11199
12199
13199
14199
15199
16199
170100
180100
190100
200100
210100
220100
23199
24199
25199
26199
27199
28199
29199
30298
31298

Wind in May

Winds average 17 km/h in May.

Across May, daily wind ranges from about 12 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
112light breeze
213light breeze
313light breeze
413light breeze
514light breeze
614light breeze
714light breeze
815light breeze
915light breeze
1015light breeze
1115light breeze
1216light breeze
1316light breeze
1416light breeze
1517light breeze
1617light breeze
1717light breeze
1817light breeze
1918light breeze
2018light breeze
2118light breeze
2218light breeze
2318light breeze
2419light breeze
2519light breeze
2619light breeze
2719light breeze
2819light breeze
2919light breeze
3019light breeze
3119light breeze

Sunrise & sunset in May

DaylightNight

Daylight runs from about 12 h 12 min at the start of May to 12 h 24 min by month's end. The lit band spans sunrise to sunset each day.

Days grow by about 12 minutes over May. Sunrise moves from 6:01 AM to 5:57 AM, and sunset from 6:15 PM to 6:19 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
112.26:016:15
212.26:006:15
312.26:006:15
412.36:006:15
512.35:596:15
612.35:596:15
712.35:596:15
812.35:596:15
912.35:596:15
1012.35:586:15
1112.35:586:15
1212.35:586:16
1312.35:586:16
1412.35:586:16
1512.35:586:16
1612.35:576:16
1712.35:576:16
1812.35:576:16
1912.35:576:17
2012.35:576:17
2112.35:576:17
2212.35:576:17
2312.35:576:17
2412.35:576:17
2512.35:576:18
2612.35:576:18
2712.45:576:18
2812.45:576:18
2912.45:576:18
3012.45:576:19
3112.45:576:19

Solar energy in May

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in May, about 4.89 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 — May's 4.89 kWh/m² falls in the middle.

0246151015202531
Solar energy (kWh/m²)Level
15.3Bright
25.3Bright
35.2Bright
45.2Bright
55.2Bright
65.1Bright
75.1Bright
85.1Bright
95.1Bright
105.0Bright
115.0Bright
125.0Bright
135.0Bright
145.0Bright
154.9Bright
164.9Bright
174.9Bright
184.9Bright
194.9Bright
204.8Bright
214.8Bright
224.8Bright
234.8Bright
244.8Bright
254.8Bright
264.7Bright
274.7Bright
284.7Bright
294.7Bright
304.7Bright
314.7Bright
Planning a trip in May

Hazard calendar for Dehiwala-Mount Lavinia

In seasonPeak

In May, 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 May a good time to visit Dehiwala-Mount Lavinia?

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

3.0
Sightseeing
12th-best month of the year
3.9
Beach & pool
12th-best month of the year

May is a weaker month for outdoor sightseeing in Dehiwala-Mount Lavinia.

What to pack for Dehiwala-Mount Lavinia in May

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

In May, Dehiwala-Mount Lavinia sees daytime highs around 29°C and nights near 27°C. Pack light clothes and rain gear. Worth having: sun protection. About 29 days see rain.

light clothesrain gearsun protection

Sea temperature near Dehiwala-Mount Lavinia in May

The nearest coast averages about 29°C in May — 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 May

LowModerateHighVery highExtreme

Clear-sky midday UV in May 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 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 May

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see where May 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
May 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).