Based on the Köppen climate classification, Mount Eielson is located in a subarctic climate zone with long, cold, snowy winters, and mild summers. Temperatures can drop below −20 °C with wind chill factors below −30 °C. The months May through June offer the most favorable weather for climbing or viewing. Precipitation runoff from the mountain drains north into tributaries of the McKinley River, which in turn is part of in the Tanana River drainage basin.