Weather is probably a major factor when you plan your trip to Galgamuwa, and keep in mind that cheaper options are usually available when the weather isn't as good. 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.