Climate and average weather in Mirissa

In Mirissa, the weather is muggy, hot, wet, and partly cloudy and remarkably steady, with daytime highs holding near hot levels all year. The wettest stretch peaks around November.

Best: mid December to mid March

Over the course of the year, the temperature in Mirissa typically varies from 24°C to 31°C, and is rarely below 22°C or above 32°C. March is the hottest month of the year, while July is the coldest.

Based on the travel score, the best time of year to visit Mirissa for warm-weather activities is from mid December to mid March.

Hottest
Mar
31°
Coldest
Jul
25°
Wettest
Nov
298 mm
Driest
Feb
84 mm
Rain / yr
2145 mm
280 wet days
Daylight
11.7–12.3 h
shortest–longest
Elevation
0 m
5.9°N
Clearest
Mar
58% cloud

Mirissa is place in Southern Province, Sri Lanka.

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

Mirissa weather by month, at a glance

The whole year in one picture — sky, rain, humidity, temperature and travel score. Click any band to jump to its full chart.

Each stripe is one measure across the whole year, stacked so a single day reads top to bottom. The sky band runs overcast grey on top down to clear blue at the base — more blue means sunnier — followed by the rainfall curve, the humidity band, a temperature strip that tints each stretch of the year by how warm its average high is, and the travel-score line at the foot. Scan straight down any date to read that day across every measure at once; the score climbs highest around mid December to mid March.

Temperature through the year

Average highAverage lowShaded bands: 10–90% of days

Daily average highs and lows in Mirissa, from 1991–2020 of climate data. The shaded bands show the range most days fall in — 10th to 90th percentile.

Temperatures in Mirissa stay fairly even through the year, without a distinct hot or cool season. The warmest month is March, with an average high of 31°C and low of 25°C; the coolest is July, with an average low of 25°C and high of 28°C.

Days typically run about 5°C warmer than nights, with the widest day–night swing (around 6°C) in February.

20°25°30°35°JanFebMarAprMayJunJulAugSepOctNovDec
Avg high (°C)Avg low (°C)
Jan2924
Feb3024
Mar3125
Apr3025
May2926
Jun2925
Jul2825
Aug2825
Sep2925
Oct2924
Nov2924
Dec2924

How hot and cold Mirissa really feels

Feels-like highFeels-like lowactual air temp

The felt-temperature range through the year — heat index on the day's high (summer humidity), wind chill on the night's low (winter wind). The dashed lines are the plain thermometer; the gap is how much hotter or colder it really feels.

On the hottest afternoons, once humidity is folded in, Mirissa feels like about 37°C (around April 25). Nearly every day a year carries some heat stress, peaking in April.

20°25°30°35°40°JanFebMarAprMayJunJulAugSepOctNovDecdangerous heat
Feels-like high (°C)Air high (°C)Feels-like low (°C)Air low (°C)
Jan33292324
Feb34302424
Mar35312425
Apr37302525
May36292626
Jun35292525
Jul33282525
Aug33282525
Sep33292525
Oct33292424
Nov33292424
Dec32292424

Average hourly temperature in Mirissa

A compact picture of the whole year, hour by hour: each column is a day, each row an hour, and the color is the modeled average temperature. Darker overlays mark night, lighter ones the civil-twilight hours around sunrise and sunset.

Read left to right for the day of the year and top to bottom for the hour of the day; the color is the modeled temperature, cool blues through to hot reds on the same scale as the other charts. A vertical slice is a single day's swing — coolest just before dawn, warmest in the mid-afternoon — while a horizontal slice follows one hour across the seasons. The darker overlay marks night and the lighter one the twilight around sunrise and sunset. Colors run warmest on March afternoons, near 31°C, and coldest before dawn in July, near 25°C.

JanFebMarAprMayJunJulAugSepOctNovDec12 AM2 AM4 AM6 AM8 AM10 AM12 PM2 PM4 PM6 PM8 PM10 PM12 AM

Mirissa weather by month

Every month at a glance. Click a month for its detailed page.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan29° / 24°9914.611.74.7
Feb30° / 24°8413.111.84.4
Mar31° / 25°10318.7123.8
Apr30° / 25°18925.712.13.1
May29° / 26°22128.112.33.0
Jun29° / 25°18726.812.33.2
Jul28° / 25°15326.512.33.5
Aug28° / 25°15826.812.23.5
Sep29° / 25°20226.3123.4
Oct29° / 24°25126.511.93.4
Nov29° / 24°29825.111.73.4
Dec29° / 24°20021.411.74.0

Chance of rain

How likely it is to rain on a typical day, and how that shifts across the wetter and drier seasons.

Mirissa gets about 2145 mm of precipitation a year. On a typical day the chance of rain is very wet, but that rises and falls sharply with the seasons.

The wetter season lasts 8.3 months, from around Mar 31 to Dec 9, peaking in May at about 93% chance on a given day. The drier stretch runs the rest of the year, bottoming out around Jan 21.

November is the wettest month by volume, with 298 mm over about 25 wet days; February is the driest, with 84 mm.

0%10%20%30%40%50%60%70%80%90%100%JanFebMarAprMayJunJulAugSepOctNovDecdrierwettermostly drysome rainoften wetvery wetMay 28 · 93%Jan 21 · 43%
Rain on a day (%)Rain days
Jan4715
Feb4713
Mar6119
Apr8426
May9028
Jun8927
Jul8627
Aug8627
Sep8726
Oct8627
Nov8325
Dec6921

Monthly rainfall

Over a full year, Mirissa collects about 2145 mm of rain across 280 wet days — roughly 179 mm in an average month.

It doesn’t fall evenly. November is the wettest month with 298 mm, while February is the driest at just 84 mm. The three wettest months alone bring about 36% of the year’s total.

050100150200250300350JanFebMarAprMayJunJulAugSepOctNovDec9984103189221187153158202251298200
Rainfall (mm)Rain days
Jan9915
Feb8413
Mar10319
Apr18926
May22128
Jun18727
Jul15327
Aug15827
Sep20226
Oct25127
Nov29825
Dec20021

Clouds and sunshine

ClearMostly clearPartly cloudyMostly cloudyOvercast

How often the daytime sky is clear, partly cloudy or overcast.

In Mirissa, the average share of the sky covered by clouds shows significant seasonal variation over the course of the year.

The clearer part of the year begins around December 9 and lasts for 4.6 months, ending around April 26. The clearest month is March, when the sky is clear, mostly clear, or partly cloudy 52% of the time on average.

The cloudier part of the year begins around April 27 and lasts for 7.4 months, ending around December 8. The cloudiest month is June, when it is overcast or mostly cloudy 84% of the time.

0%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%JanFebMarAprMayJunJulAugSepOctNovDecMar 13 · 54%Jun 6 · 13%clearmostly clearpartly cloudymostly cloudyovercastclearercloudier
Clearer (%)Cloudier (%)
Jan4159
Feb4555
Mar5248
Apr3664
May2179
Jun1684
Jul1684
Aug1783
Sep1981
Oct2278
Nov2278
Dec3169

Daylight, sunrise and sunset

DaylightNight

Hours of daylight through the year, with sunrise and sunset times.

The gold band is daylight — sunrise runs along its lower edge, sunset along the upper — so it widens toward summer and pinches toward winter, with night the dark area above and below. Close to the equator, Mirissa barely changes through the year: days stay near 12 h 18 min of light in every season.

12 AM4 AM8 AM12 PM4 PM8 PM12 AMJanFebMarAprMayJunJulAugSepOctNovDec
Daylight (h)Sunrise (AM)Sunset (PM)
Jan11.76:276:08
Feb11.86:296:17
Mar12.06:196:17
Apr12.16:046:12
May12.35:566:13
Jun12.35:586:19
Jul12.36:046:23
Aug12.26:066:18
Sep12.06:026:03
Oct11.95:575:49
Nov11.76:025:45
Dec11.76:155:54

Sunny days

How many genuinely sunny days each month brings — days the sky stays clear or mostly clear — banded into plain-language zones.

Mirissa averages about 3 sunny days a month — counting the days the sky stays clear or mostly clear — with a clear seasonal swing between 1 and 9 days.

The sunnier stretch runs 4.4 months, from around Dec 13 to Apr 26. The sunniest month is March, with roughly 8 sunny days (mixed).

The greyest month is September, down near 1 sunny days — about 86% fewer than the March peak.

051015JanFebMarAprMayJunJulAugSepOctNovDecsunniergreyergloomymixedMar 79 daysSep 151 days
Sunny daysSky
Jan7Gloomy
Feb7Gloomy
Mar8Mixed
Apr4Gloomy
May2Gloomy
Jun1Gloomy
Jul1Gloomy
Aug1Gloomy
Sep1Gloomy
Oct2Gloomy
Nov2Gloomy
Dec4Gloomy

Humidity comfort

DryComfortableHumidMuggyOppressiveMiserable

Share of days at each humidity comfort level, based on the dew point — the measure that tracks how muggy it actually feels.

Humidity comfort is graded by the dew point — the temperature at which the air would be fully saturated — because it tracks how muggy it actually feels far better than relative humidity does. A low dew point feels dry and crisp; a high one feels sticky and oppressive no matter the reading on a humidity gauge.

Mirissa is humid all year round — on a typical day the air feels at least humid, and there is no real dry season to wait for.

The stickiest month is January, when it feels muggy, oppressive or miserable about 100% of the time. Even in January, the mildest month, the air is dry or comfortable only 0% of the time.

0%10%20%30%40%50%60%70%80%90%100%JanFebMarAprMayJunJulAugSepOctNovDecoppressivemiserablemuggy
Muggy (%)Oppressive (%)Miserable (%)
Jan11862
Feb12835
Mar36632
Apr01783
May0595
Jun01684
Jul04357
Aug04852
Sep05149
Oct05842
Nov07624
Dec38512

Wind

Average wind speed through the year, banded into plain-language speed zones so a number reads as 'breezy' or 'calm' without knowing the scale.

This is the average sustained wind speed at the standard 10 metres above open ground — the steady flow a weather station reports, not the sharper gusts that come and go, which can run half again as fast. It's the number that says whether a place is generally breezy or calm.

Across the year, average wind speed in Mirissa is typically light breeze, near 13 km/h, and varies a lot with the seasons.

The windier part of the year lasts 5.6 months, from around May 4 to Oct 19. The windiest month is July, averaging about 20 km/h (light breeze).

The calmer part of the year runs from around Oct 20 to May 3, with January the calmest month at about 7 km/h.

0510152025JanFebMarAprMayJunJulAugSepOctNovDeccalmerwindiercalmercalmlight breezebreezyJul 17 · 20 km/hJan 17 · 7 km/h
Wind speed (km/h)Feels
Jan7calm
Feb8calm
Mar8calm
Apr10calm
May16light breeze
Jun19light breeze
Jul20light breeze
Aug19light breeze
Sep17light breeze
Oct13light breeze
Nov9calm
Dec8calm

Hazard calendar for Mirissa

In seasonPeak

When the seasonal hazards worth planning around — the rainy season, tropical-cyclone risk and dust haze — are active through the year.

Mirissa 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

Best time to visit Mirissa

TravelBeach/poolTemperatureCloudsPrecipitation

To characterize how pleasant the weather is in Mirissa throughout the year, we compute two travel scores — one for general sightseeing, one for beach and pool weather.

Around early March, Mirissa is still near the tail of its best-weather window — great conditions with the peak-season crowds already thinning.

Inferred from the travel-score curve; month-by-month visitor numbers are a planned addition.

The travel score favors clear, rainless days with daytime highs between 18°C and 28°C. Based on this score, the best time of year to visit Mirissa for general outdoor tourist activities is from mid December to mid March, with a peak score in the third week of January.

0246810JanFebMarAprMayJunJulAugSepOctNovDecbest timetravel scoretemperaturecloudsprecipitationJan 17 · 4.8

The travel score (filled area), and its constituents: the temperature score (red line), the cloud cover score (blue line), and the precipitation score (green line).

Travel score (0–10)Rating
Jan4.7fair
Feb4.4fair
Mar3.8fair
Apr3.1poor
May3.0poor
Jun3.2poor
Jul3.5poor
Aug3.4poor
Sep3.4poor
Oct3.4poor
Nov3.5poor
Dec4.0fair

The beach/pool score favors clear, rainless days with daytime highs between 24°C and 34°C. Based on this score, the best time of year to visit Mirissa for hot-weather activities is from mid December to late March, with a peak score in the third week of January.

024681012JanFebMarAprMayJunJulAugSepOctNovDecbest timebeach/pool scoretemperaturecloudsprecipitationJan 20 · 6.3

The beach/pool score (filled area), and its constituents: the temperature score (red line), the cloud cover score (blue line), and the precipitation score (green line).

What to pack for Mirissa, by month

EssentialRecommendedOptional

Month by month, what's worth putting in the bag — from the temperature range, rain chance, sun and wind. Tap a month for a quick packing note.

Mirissa packs about the same all year — highs hold near 31°C. Across the year the things worth having are light clothes, rain gear, sun protection and a windbreaker.

Light clothing
Warm layer
Winter coat
Rain gear
Sun protection
Windbreaker

In March, Mirissa sees daytime highs around 31°C and nights near 25°C. Pack light clothes, rain gear and sun protection. About 19 days see rain.

Sea temperature near Mirissa

Average ocean temperature at the nearest coast, month by month, banded into swim-comfort zones — the other half of the beach question.

The sea offshore is warmest in April at about 30°C and coldest in July near 28°C.

The water stays above 20°C all year — warm enough for a swim any month.

26°28°30°JanFebMarAprMayJunJulAugSepOctNovDecwarmtropicalcomfortable to swim
Sea temperature (°C)Comfort
Jan28Warm
Feb28Tropical
Mar29Tropical
Apr30Tropical
May29Tropical
Jun28Tropical
Jul28Warm
Aug28Warm
Sep28Warm
Oct28Tropical
Nov29Tropical
Dec28Tropical

UV index (midday) in Mirissa by month

LowModerateHighVery highExtreme

Clear-sky midday UV index through the year, shaded by the WHO exposure levels — how much sun protection each month calls for.

Under clear skies, the midday UV index in Mirissa peaks around April 17 at about 14 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near January 11 at about 9 (very high).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecExtremeApr 17UV 14Jan 11UV 9
UV index (midday)Level
Jan9Very high
Feb14Extreme
Mar12Extreme
Apr14Extreme
May13Extreme
Jun11Extreme
Jul11Extreme
Aug13Extreme
Sep13Extreme
Oct13Extreme
Nov11Extreme
Dec10Very high

Average hourly UV index in Mirissa

LowModerateHighVery highExtreme

Modeled clear-sky UV for every hour of every day — when in the day sun protection actually matters.

The whole year hour by hour: each column is a day, each row an hour, and the color is the modeled clear-sky UV index — the midday peak scaled down as the sun sits lower in the sky. Darker overlays mark night, lighter ones the civil-twilight hours around sunrise and sunset.

UV falls off far faster than brightness as the sun drops, so even in April the burn window is concentrated in the middle of the day: about 8 hours a day reach index 3 (protection recommended), and 6.5 hours reach 6 or more. Mornings and late afternoons stay comparatively gentle year round.

JanFebMarAprMayJunJulAugSepOctNovDec12 AM2 AM4 AM6 AM8 AM10 AM12 PM2 PM4 PM6 PM8 PM10 PM12 AM
UV ≥ 3 (h/day)UV ≥ 6 (h/day)
Jan75
Feb86
Mar86
Apr86.5
May86
Jun85.5
Jul86
Aug86
Sep86.5
Oct7.56
Nov7.55.5
Dec75

Air quality in Mirissa by month

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see which months the air is worst, not just the yearly average.

Air quality in Mirissa is worst in January — around 35 µg/m³ PM2.5 (moderate), about 2.1× the cleanest month (September, 16 µg/m³).

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

010203040JanFebMarAprMayJunJulAugSepOctNovDecModerateJan 1834 µg/m³Sep 1316 µg/m³
PM2.5 (µg/m³)Level
Jan35Moderate
Feb31Moderate
Mar25Moderate
Apr21Moderate
May20Moderate
Jun18Moderate
Jul17Moderate
Aug17Moderate
Sep16Moderate
Oct18Moderate
Nov25Moderate
Dec30Moderate
Almanac & agriculture

Growing season

Chance of a frost-free dayFrost-free year round

Mirissa is frost-free year round — even the coldest nights rarely reach freezing, so there is no start or end to the growing season.

0%25%50%75%100%JanFebMarAprMayJunJulAugSepOctNovDecfrost-free year round
Frost-free chance (%)Frost nights
Jan1000
Feb1000
Mar1000
Apr1000
May1000
Jun1000
Jul1000
Aug1000
Sep1000
Oct1000
Nov1000
Dec1000

Growing degree days

Degree days (base 10°C)Frost-free shaded

Growing degree days tally heat above 10°C: each day adds however many degrees its average temperature runs over that threshold, and cold days add nothing. Mirissa banks about 6,151 degree days a year, and the running total — which growers use to time plantings and predict maturity — climbs fastest around April.

02,0004,0006,000JanFebMarAprMayJunJulAugSepOctNovDec
Growing degree days (°C·days)
Jan509
Feb475
Mar542
Apr528
May542
Jun511
Jul518
Aug515
Sep497
Oct513
Nov494
Dec507

Solar energy

Average daily shortwave solar energy reaching the ground, banded into brightness zones so the number means something at a glance.

Solar energy is how much sunlight actually reaches the ground each day, measured in kilowatt-hours per square metre (kWh/m²) — the combined effect of how long the sun is up, how high it climbs, and how much cloud gets in the way. It's the raw fuel a solar panel has to work with: for scale, 1 kWh/m² a day is dim and wintry, while 7+ is desert-bright.

Mirissa receives about 5.5 kWh/m² a day of solar energy on average — bright — with a clear seasonal swing between 4.8 and 6.4 kWh/m².

The brighter stretch of the year lasts 3.5 months, from around Jan 16 to May 3. The brightest month is March, averaging about 6.4 kWh/m² (intense).

The dimmest month is November, down near 4.9 kWh/m² — roughly 24% less than the March peak.

012345678JanFebMarAprMayJunJulAugSepOctNovDecbrighterdimmerdimmoderatebrightintenseMar 176.4 kWhNov 224.8 kWh
Solar energy (kWh/m²)Level
Jan5.5Bright
Feb6.1Intense
Mar6.5Intense
Apr5.9Bright
May5.4Bright
Jun5.3Bright
Jul5.4Bright
Aug5.6Bright
Sep5.5Bright
Oct5.3Bright
Nov4.8Bright
Dec4.9Bright

Where is Mirissa?

Mirissa sits at 5.9°N, 80.5°E, 0 m above sea level, in Sri Lanka. The nearest listed city is Weligama, 4.0 km away.

UnawatunaGalleBeliattaAmbalangodaAmbalantota

Topography around Mirissa

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

Within 3 km, the terrain around Mirissa has only modest variations in elevation — a maximum elevation change of 57 m around an average of 5 m above sea level; within 16 km, significant variations in elevation — a maximum elevation change of 291 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,507 m.

The land around Mirissa is covered by water (60%) and trees (34%) within 3 km, water (54%) and trees (37%) within 16 km, and trees (52%) and water (44%) within 80 km.

3 km
57 m
16 km
291 m
80 km
1,507 m
treesgrasslandcroplandartificial surfaceswaterwetland
Nearby: Weligama 4.0 km · Matara 9.0 km · Devinuwara 15 km · Unawatuna 24 km · Galle 30 km · Beliatta 32 km · Ambalangoda 55 km · Ambalantota 65 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 Mirissa (5.9466°, 80.4583°, elevation 0 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).