Taking into account the local weather in Barnstead is an important factor for planning your visit, especially if you plan to spend your trip poolside. The hottest months are usually July and August with an average temp of 67°F, while the coldest months are January and February with an average of 27°F. The snowiest months in Barnstead are January, April, March, and February, with each month seeing an average of 13 inches of snowfall.