Taking into account the local weather in Galgamuwa is an important factor for planning your visit, especially if you plan to spend your trip poolside. The hottest months are usually April and March with an average temp of 82°F, while the coldest months are January and February with an average of 78°F. The rainiest months in Galgamuwa are November, October, December, and April, with each month seeing an average of 9 inches of rainfall.