Based on the Köppen climate classification, Mount Selwyn is located in a subarctic climate zone with cold, snowy winters, and mild summers.[5] Temperatures can drop below −20 °C with wind chill factors below −30 °C. This climate supports an intensely glaciated area around the mountain including the Fox Glacier on the north aspect, The Bishops Glacier on the south, the Deville Névé to the southeast, and the Deville Glacier to the east. Precipitation runoff from the mountain drains into the Beaver River.
^Boles, Glen W. (2006). Canadian Mountain Place Names. Rocky Mountain Books. p. 224.
^Peel, M. C.; Finlayson, B. L.; McMahon, T. A. (2007). "Updated world map of the Köppen−Geiger climate classification". Hydrol. Earth Syst. Sci. 11: 1633–1644. ISSN1027-5606.