Dehiwala-Mount Lavinia in Summer
In summer (June, July and August), Dehiwala-Mount Lavinia sees average daytime highs around 28°C and overnight lows near 26°C, with 645 mm of rain over about 76 wet days across the season. It is the coldest season of the year and the 2nd-wettest season.
Across summer, daytime highs hold fairly steady around 28°C. The sky is clear or mostly clear about 5% of the time across summer, and the air most often feels miserable.
Summer is Dehiwala-Mount Lavinia's 3rd-best season to visit on our travel score. Dehiwala-Mount Lavinia has little temperature swing across the year, so its calendar seasons blur — the season framing matters less here than for a place with four distinct seasons. For the whole year in context, see Dehiwala-Mount Lavinia's year-round climate.
- Avg daytime high
- 28°C
- coldest season of the year
- Avg overnight low
- 26°C
- Rainfall
- 645 mm
- 76 wet days
- Avg wind
- 20 km/h
- Travel score
- 3.6
- 3rd-best season
- Months
- Jun · Jul · Aug
Temperature in Dehiwala-Mount Lavinia in Summer
Across summer, daytime highs hold fairly steady around 28°C.
A typical summer day in Dehiwala-Mount Lavinia reaches about 28°C and drops to 26°C overnight. The warmest of the three months is June, the coolest August.
How summer really feels in Dehiwala-Mount Lavinia
Once humidity and wind are folded in, summer brings about 92 days that feel above 32°C and 0 that feel at or below 0°C.
The story in summer is heat — humidity pushes the afternoon "feels like" well above the raw temperature.
Dehiwala-Mount Lavinia weather by month
How the three summer months (June, July and August) compare with the rest of the year — the season's months are highlighted.
| Month | High / Low (°C) | Rainfall (mm) | Wet days | Daylight (hours) | Travel score |
|---|---|---|---|---|---|
| Jan | 30° / 25° | 60 | 8.8 | 11.6 | 5.4 |
| Feb | 30° / 25° | 57 | 8.5 | 11.8 | 5.2 |
| Mar | 30° / 26° | 75 | 14.9 | 12 | 4.5 |
| Apr | 30° / 26° | 174 | 24.4 | 12.1 | 3.3 |
| May | 29° / 27° | 293 | 29 | 12.3 | 3.0 |
| Jun | 29° / 26° | 257 | 26.5 | 12.4 | 3.3 |
| Jul | 28° / 26° | 205 | 25.3 | 12.4 | 3.7 |
| Aug | 28° / 26° | 183 | 24.6 | 12.2 | 3.8 |
| Sep | 28° / 26° | 232 | 24.3 | 12 | 3.7 |
| Oct | 28° / 25° | 328 | 26 | 11.8 | 3.6 |
| Nov | 29° / 25° | 330 | 23.8 | 11.7 | 3.7 |
| Dec | 29° / 25° | 175 | 16.7 | 11.6 | 4.6 |
Cloud cover in Summer
The sky is clear or mostly clear about 5% of the time across summer.
Chance of precipitation in Summer
Dehiwala-Mount Lavinia gets around 645 mm of rain over 76 wet days across summer. The line is the day-by-day chance of measurable precipitation.
Humidity in Summer
Most of summer feels miserable — the stacked bands show each day's mix of comfort levels, read off the dew point.
Wind in Summer
Winds average 20 km/h across summer.
Sunrise & sunset in Summer
Daylight runs from about 12 h 24 min in early June to 12 h 06 min by late August. The lit band spans sunrise to sunset each day.
Solar energy in Summer
Average shortwave solar energy reaching the ground each day across summer, about 5.0 kWh/m².
Hazard calendar for Dehiwala-Mount Lavinia
In summer, Dehiwala-Mount Lavinia overlaps 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.
Is summer a good time to visit Dehiwala-Mount Lavinia?
Our two travel scores rate summer for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal), averaged across the three months.
summer is a weaker month for outdoor sightseeing in Dehiwala-Mount Lavinia.
What to pack for Dehiwala-Mount Lavinia in Summer
From summer's temperature range, rain chance, sun and wind — what's worth putting in the bag.
In summer, Dehiwala-Mount Lavinia sees daytime highs around 28°C and nights near 26°C. Pack light clothes and rain gear. Worth having: sun protection. About 76 days see rain.
Sea temperature near Dehiwala-Mount Lavinia in Summer
The nearest coast averages about 28°C across summer — 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.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sea temperature (°C) | 28 | 28 | 29 | 30 | 29 | 28 | 28 | 27 | 28 | 28 | 29 | 28 |
| Comfort | Warm | Tropical | Tropical | Tropical | Tropical | Tropical | Warm | Warm | Warm | Tropical | Tropical | Tropical |
| Sea temperature (°C) | Comfort | |
|---|---|---|
| Jan | 28 | Warm |
| Feb | 28 | Tropical |
| Mar | 29 | Tropical |
| Apr | 30 | Tropical |
| May | 29 | Tropical |
| Jun | 28 | Tropical |
| Jul | 28 | Warm |
| Aug | 27 | Warm |
| Sep | 28 | Warm |
| Oct | 28 | Tropical |
| Nov | 29 | Tropical |
| Dec | 28 | Tropical |
UV index in Dehiwala-Mount Lavinia in Summer
Clear-sky midday UV across summer averages 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.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UV index (midday) | 10 | 12 | 12 | 12 | 12 | 11 | 11 | 13 | 13 | 12 | 10 | 10 |
| Level | Extreme | Extreme | Extreme | Extreme | Extreme | Extreme | Extreme | Extreme | Extreme | Extreme | Extreme | Very high |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 10 | Extreme |
| Feb | 12 | Extreme |
| Mar | 12 | Extreme |
| Apr | 12 | Extreme |
| May | 12 | Extreme |
| Jun | 11 | Extreme |
| Jul | 11 | Extreme |
| Aug | 13 | Extreme |
| Sep | 13 | Extreme |
| Oct | 12 | Extreme |
| Nov | 10 | Extreme |
| Dec | 10 | Very high |
Air quality in Dehiwala-Mount Lavinia in Summer
Average fine-particle pollution (PM2.5) through the year — so you can see where summer 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).
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| PM2.5 (µg/m³) | 36 | 37 | 36 | 28 | 24 | 19 | 18 | 18 | 18 | 20 | 30 | 34 |
| Level | Poor | Poor | Poor | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate |
| PM2.5 (µg/m³) | Level | |
|---|---|---|
| Jan | 36 | Poor |
| Feb | 37 | Poor |
| Mar | 36 | Poor |
| Apr | 28 | Moderate |
| May | 24 | Moderate |
| Jun | 19 | Moderate |
| Jul | 18 | Moderate |
| Aug | 18 | Moderate |
| Sep | 18 | Moderate |
| Oct | 20 | Moderate |
| Nov | 30 | Moderate |
| Dec | 34 | Moderate |
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.
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
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.