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Sri Lanka
Mirissa weather by month
Historical averages 2016–2025 · not a forecast
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When is the best time to visit Mirissa?
For a warm holiday, the best week has been 10–16 August (Weather Index 84). Favourable start dates for a 7-day trip run from 2 August to 19 August. February, March and April are warmest (31°C), February is driest and February to April and June to August have the most sun.
- Warmest
- February, March and April 31°C
- Coolest
- July to October 29°C
- Driest
- February 39% rain-day chance
- Wettest
- May 93% rain-day chance
- Sunniest
- February to April and June to August 11 hours a day
A rain day has 1 mm or more, snow included, so a short shower counts. Monthly averages below give the amounts.
Monthly averages in Mirissa
Mirissa historical monthly estimates, 2016–2025. Temperatures and sunshine are daily averages.
| Month | High (°C) | Low (°C) | Rain-day chance (%) | Expected rain days | Precipitation (mm/month) | Sunshine (hours/day) |
|---|---|---|---|---|---|---|
| January | 30.2 | 24.3 | 51.9 | 16.1 | 133.8 | 10.4 |
| February | 31.4 | 24.6 | 39.3 | 11.0 | 70.0 | 11.2 |
| March | 31.3 | 25.2 | 64.8 | 20.1 | 110.0 | 10.9 |
| April | 31.1 | 25.7 | 84.0 | 25.2 | 168.9 | 10.8 |
| May | 30.2 | 26.2 | 92.9 | 28.8 | 292.6 | 9.8 |
| June | 29.7 | 26.1 | 89.7 | 26.9 | 171.4 | 11.0 |
| July | 29.5 | 25.9 | 81.6 | 25.3 | 139.9 | 10.8 |
| August | 29.3 | 25.7 | 80.3 | 24.9 | 155.2 | 10.6 |
| September | 29.3 | 25.4 | 88.3 | 26.5 | 191.2 | 10.2 |
| October | 29.3 | 25.1 | 84.5 | 26.2 | 247.3 | 9.5 |
| November | 29.6 | 24.9 | 83.0 | 24.9 | 306.4 | 8.8 |
| December | 29.8 | 24.7 | 68.4 | 21.2 | 179.7 | 9.7 |
Each month averages its own days. Precipitation includes snow. About the data
Sources
Open-Meteo · 1 Jan 2016 – 31 Dec 2025
- Open-Meteo Historical Weather API
- Local days, 2016–2025, every year weighted equally. Each weekly chart averages its own seven days, without smoothing.
- Shading shows the 10th–90th percentile of past days, not forecast confidence.
- A rain day has at least 1 mm, snow included. The last weekly period has eight days.
- Wind is the average daytime (10:00–18:00) maximum, not gusts. Daylight is calculated from latitude. Missing readings stay blank.
- Mugginess (dew point) comes from the original daily summaries, on UTC days.
- The live two-week forecast comes from the Open-Meteo Weather Forecast API. The Weather Index does not use it.