A Dutch colonial fort, palm coves and whale watching on the island's south coast. Southern sri lanka barely has a temperature season: daytime highs move only about 2 °C across the whole year, from 28 °C in August to 30 °C in March. What changes instead is rain.
On a strict reading, no month in southern Sri Lanka clears every threshold for a beach trip — the limits below are absolute, not relative to the region. That does not make it a bad destination; it means the trip has to be planned around a specific constraint rather than a season.
The binding constraint here is rainfall — that is what rules months out, not any composite judgement. Rainfall is sharply seasonal: November averages 279 mm against 73 mm in February, so the wet season is the real planning constraint rather than heat or cold. January is the weakest month on these criteria.
Month by month
| Month | High °C | Low °C | Precip mm | Wet days |
|---|---|---|---|---|
| January | 29 | 23 | 119 | 16.7 |
| February | 30 | 24 | 73 | 14.2 |
| March | 30 | 25 | 122 | 21.2 |
| April | 30 | 25 | 191 | 26.7 |
| May | 29 | 25 | 234 | 28.9 |
| June | 29 | 25 | 207 | 27.9 |
| July | 28 | 25 | 175 | 27.6 |
| August | 28 | 25 | 171 | 27.7 |
| September | 28 | 25 | 210 | 26.9 |
| October | 28 | 24 | 276 | 27.4 |
| November | 28 | 24 | 279 | 25.6 |
| December | 28 | 24 | 230 | 22.7 |
Ticked rows are months where every hard requirement for a beach trip is met across at least half the month.
Open Southern Sri Lanka on the map →Nearby regions
Figures are 30-year climatology sampled at Galle, Mirissa, Unawatuna, Tangalle and Weligama, averaged across those locations, from ERA5-Land reanalysis fitted with a harmonic seasonal cycle and a trend term, evaluated for 2026. Sampling named towns rather than averaging the whole region avoids blending valley and mountain conditions into a figure true of neither. Cells are about 0.08° wide, from ERA5-Land's 0.1° grid, which is itself driven by a 0.25° (~28 km) atmospheric reanalysis — so individual valleys, sheltered bays and single summits are not resolved. In steep terrain read these as conditions for the wider area rather than for one village. They describe typical conditions, not a forecast. Read how the climatology is built.