Based on the Köppen climate classification, Sisqa Peak is located in the marine west coast climate zone of western North America. Most weather fronts originating in the Pacific Ocean travel east toward the Coast Mountains where they are forced upward by the range, causing them to drop their moisture in the form of rain or snowfall. As a result, the Coast Mountains experience high precipitation, especially during the winter months in the form of snowfall. Winter temperatures can drop below −10 °C with wind chill factors below −20 °C.