Anchorage has a subarctic climate (the Köppen climate classification is Dfc) due to its short, cool summers. Average daytime summer temperatures range from approximately 55 to 78 degrees Fahrenheit (13 to 26 degrees Celsius); average daytime winter temperatures are about 5 to 30 degrees (-15 to -1 degrees Celsius). Anchorage has a frost-free growing season that averages slightly over 100 days.
Average January low and high temperatures at Ted Stevens Anchorage International Airport (PANC) are 9 °F/22 °F (-13 °C/-5 °C) with an average winter snowfall of 70.60 inches (179.3 cm). The 1954-1955 winter had 132.8 inches (337.3 cm), which made it the snowiest winter on record. The coldest temperature ever recorded at the original weather station located at Merrill Field on the East end of 5th Avenue was -38 °F (-38.8 °C) on February 3, 1947.
Summers are typically mild (although cool compared to the contiguous US and even interior Alaska), though it can rain frequently. Average July low and high temperatures are 52 °F/66 °F (11 °C/19 °C) and the hottest reading ever recorded was 92 °F (33.3 °C) on June 25, 1953. The average annual precipitation at the airport is 16.07 inches (408 mm).
Owing to its proximity to active volcanoes, ash hazards are a significant, though infrequent, occurrence. The most recent notable incident was an August 1992 eruption of Mount Spurr, which is located 78 miles west of the city. The eruption deposited about 3 mm of volcanic ash on the city. The clean-up of ash resulted in excessive demands for water and caused major problems for the Anchorage Water and Wastewater Utility.
Because of Anchorage's latitude, summer days are very long and winter daylight hours are very short. Anchorage is often cloudy during the winter, which decreases the amount of sunlight experienced by residents.