March is the final full month of reliable dry weather on the south coast and it is a genuinely excellent time to visit. The crowds from the peak January and February season have thinned, prices at most guesthouses and restaurants have come down from their seasonal high, and the weather is still very good for most of the month. The surfers and beach-goers who arrive in March often say it feels like the version of the coast they imagined before they came: good conditions, good food, and enough space to actually enjoy both.
The weather in March runs at 28 to 32 degrees Celsius, slightly warmer than January and February. The sky is mostly clear and sunny. Rainfall remains low through most of the month, though by the last week or two of March there can be an increase in cloud cover and occasional afternoon showers as the coast edges toward the pre-monsoon transition. This does not ruin a March trip. It is not the monsoon. It is the tail end of the dry season, and the difference between a good March day and a good January day is minimal. What changes is the predictability: January is almost always clear, March is almost always clear but not quite with the same certainty.
Whale watching in March is very good, particularly in the first two to three weeks. Blue whale sightings from Mirissa are still at high frequency through mid-March. By the second half of March, the season starts to wind down. Boats are still running and sightings still happen, but the peak is behind you. If whale watching is essential and your dates fall in late March, the trip is still worth making, but temper expectations slightly compared to January and February.
Surfing in March is excellent and in some years produces the best waves of the entire season. A late dry season swell can create very clean conditions at all the main breaks. Hiriketiya, Ahangama, and Weligama are all surfing well in March. The lineups are noticeably less crowded than February. If you surf and want good waves without the competition for them that comes in peak season, March delivers.
Prices in March are meaningfully lower than January at most mid-range and budget guesthouses. Luxury boutique properties tend to hold their rates through the season, but the independently run guesthouses that make up most of the south coast accommodation scene are generally more negotiable by March. For couples or solo travellers on a budget who want good weather, March is the best value month of the dry season.
April is the question that comes up when people are considering March. The first half of April is usually fine and the second half can bring the beginning of the southwest monsoon. If your trip runs into April, plan for the possibility of some rough weather toward the end. A trip that is mostly March with a few days of April is a good outcome. A trip that is mostly April is riskier. For the clearest and most honest picture of what April specifically looks like, it is covered in the general weather guide on this blog.