Sri Lanka Weather by Month: When the South Coast Is Dry, and Where to Go When It Isn't

What is the weather in Sri Lanka by month, in one minute?

Sri Lanka is a hot, humid island close to the equator, so the year is not summer and winter. It is a sequence of wetter and drier spells, driven by two monsoons. On the south coast, where Ahangama and Weligama sit, highs stay between 28°C and 31°C in every month. What changes is rain, cloud and wind. The year at Ahangama:

Averages 2015-2025 · Source: Open-Meteo, CHIRPS · How we measure

Weligama is about 5 km away on the same weather-model grid and reads within a few millimetres of Ahangama in most months, so we show one of the two. Read the rain line: a low stretch from January to March, a first peak in May, a lull from June to August, then the biggest peak from September to November.

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When is the best time to visit Sri Lanka's south coast?

February, then January and March: 77 mm in February, 92 mm in January and 96 to 100 mm in March, with 29°C to 31°C highs, 23°C to 24°C nights and cloud of 57 to 66 percent. That is the real window for a one-to-three-month stay, and the one most people mean by "dry season".

Two things catch people. The window is three months, not five: December still has about 154 mm, and April already has 138 to 152 mm. And "dry" is relative: a few wet spells with long dry runs between them, not a desert. For January to April in detail, see the south coast guide.

Why is Sri Lanka's east coast best in May to September?

The south-west monsoon brings rain to the south and west of the island, roughly from May. The north-east monsoon brings it to the north and east, roughly from November. Between them are two short in-between spells, around April and around October, when storms build in the afternoon almost anywhere.

Our data shows the south-west side clearly. We hold no east-coast place, so the east is described by travel guides, not our numbers: they put its good weather at roughly May to September, when the south coast is wet, and its rain from about October. Treat that as a lead to check.

How wet is the south coast from May to October?

Wet, in two peaks. May is 317 to 323 mm. June to August are lower, 158 to 216 mm. September and October are 369 to 385 mm, and November 291 to 297 mm.

So June to August is not the worst stretch, but it is not dry either: cloud covers 82 to 83 percent of the sky and the wind roughly doubles against January to March. That matters on a coast where the sea is the point: expect rough, swell-heavy water in the south-west monsoon months and a calmer sea from January to March. We do not measure swell or currents, so check local conditions before you swim.

Which months for a one-to-three-month stay?

• January to March: the clear first choice. February is the driest.
• December: fine as a lead-in. Plan the first weeks around showers.
• April: warm, 30°C, but showery. Fine if your days are mostly indoor work.
• May to November: only if rent is the priority, or you have gone for the east coast. September to November is the wettest run of the year here.

If you are choosing between places for the same months, our January list and February list show where else is warm and dry.

Is it a good escape from Chiang Mai's burning season?

The timing fits. Chiang Mai is smoky from about February to April (see Chiang Mai weather by month), and the south coast is at its best in February and March.

April is the weak point: the south coast is already showery, while Chiang Mai's rains, which clear the smoke, only arrive in May. From May to October both places are wet, so the south coast works as a base for the first months of the year, not as a year-round one.