For the energetic Sri Lanka traveller, eager to see as much of the island as possible, March is an attractive month to visit Sri Lanka with the weather settled across the island.
It's hotter now on the south and west coasts with peak temperatures pushing above 30C and humidity slightly higher than earlier in the year, but you are unlikely to see much in the way of rainfall. The kite-surfing season brings extra life to the north-west beaches of Kalpitiya.
The Cultural Triangle, dry and hot now, can expect peak temperatures heading towards 35C with lots of blue skies. The capital, Colombo, is also at its hottest from March to May, but in March it remains largely dry.
March is also one of the finest months to visit the hill country capital of Kandy and, above it, the peaks of the highlands. You can anticipate lots of dry, sunny weather, perfect temperatures heading towards the mid-20s and less need now for a light sweater to protect you from those cool evenings.
Just the time also to climb up Adam's Peak, although you have entered pilgrimage season, so it could be busier than normal. If Easter is in March, remember that it will make pressure on accommodation particularly high, especially in the hills.