 While Reindeer Island lacks a weather station, the entirety of southern Manitoba has a four-season humid continental climate with strong seasonal differences.Winters lack any moderation since the lake freezes over for several months, whereas at onshore stations nearer the north of the lake such as Grand Rapids see seasonal lag in spring and lower diurnal temperature variation in summer than in Winnipeg and the provinces' southern landmass, likely to be even stronger on an offshore island within the lake.It was thought that the Caspian tern used the west coast of Reindeer Island as a breeding ground, as discovered by Eric Dunlop, a naturalist, who was collecting samples for the Carlisle Museum in Carlisle, England during 1914 and 1915.