Due to its location at the base of the Northern Black Hills and proximity to the Semi-Arid High Plains to the North, Spearfish has a unique climate for its latitude. Using the Koppen climate classification system, Spearfish has a Humid Subtropical Climate (Cfa) that borders on a Mediterranean Influenced Continental Climate (Dsa) as Summers are quite dry.
Spearfish has four distinct seasons, a Hot and dry summer, a temperate fall and spring, and moderately cold and snowy winter. Winters in Spearfish are variable and often temperate as the area benefits from warm Chinook winds that come downward into the valley from the Northern Hills. It is not uncommon to have 50-60 degree days in January and February and snow cover rarely lasts long in the valley.
Excluding sporadic cold and heat fronts during winter and summer months, Spearfish has temperate weather and can be enjoyed year around. A similar climate to Spearfish is Salt Lake City Utah which is also located in a transitional zone.