Understanding Ketchikan temperatures by month is essential for planning a visit to this rainforest city on Alaska's Inside Passage. The region experiences a marine west coast climate, characterized by mild winters and cool summers moderated by the Pacific Ocean. Unlike interior Alaska, Ketchikan rarely sees extreme cold or intense heat, making it accessible year-round for travelers seeking temperate conditions.
Seasonal Temperature Overview
Annual averages in Ketchikan hover around 48°F (9°C), reflecting the powerful influence of the surrounding water. The narrow temperature range between seasons means that summer and winter feel less extreme than in continental climates. Visitors will find that layers are the defining feature of dressing in Southeast Alaska, as conditions can shift significantly within a single day.
Winter Temperatures (December to February)
Winter in Ketchikan is remarkably mild compared to other parts of the state. Average daytime highs typically range from 38°F to 42°F (3°C to 6°C), while overnight lows usually stay between 25°F and 30°F (-4°C to -1°C). Snowfall is infrequent and rarely accumulates, though rain is a constant presence during these months. The lack of extreme cold makes winter an excellent time for fishing and observing bald eagles without the summer crowds.
January Coldest Month
January stands as the coldest month of the year, with average temperatures falling between 35°F and 40°F (2°C and 4°C). While temperatures can dip into the low 30s°F (0°C) on occasion, sustained freezes are uncommon. The primary distinction of January is the limited daylight, with only about 8 hours of sun, which encourages a more relaxed, indoor pace of exploration.
Spring Transition (March to May)
Spring in Ketchikan is a season of gradual warming and lengthening days. March often feels like an extension of winter, with temperatures still hovering in the 40s°F (4°C to 7°C). By April, increased sunshine begins to thaw the landscape, and temperatures climb into the 50s°F (10°C to 14°C). May is particularly pleasant, with average highs reaching the mid-60s°F (18°C) and vibrant greenery emerging throughout the Tongass National Forest.
Summer Temperatures (June to August)
Summer is the peak tourist season, and Ketchikan temperatures during these months are ideal for outdoor activities. June and July offer the longest daylight and most stable weather, with averages in the low to mid-70s°F (21°C to 23°C). It is rare for the mercury to exceed 80°F (27°C), ensuring that hiking, kayaking, and wildlife viewing remain comfortable even during the warmest parts of the day.
July Warmest Month
July represents the warmest period of the year, though it maintains a refreshing crispness. Average high temperatures usually reach the mid-70s°F (23°C), with overnight lows in the 50s°F (10°C to 12°C). The abundant sunshine and moderate humidity create perfect conditions for exploring the coastal inlets and observing salmon runs in the region's rivers.
Autumn Conditions (September to November)
Autumn brings a swift and stunning transition to cooler weather. September often extends the summer feel, with temperatures in the 60s°F (15°C to 17°C) and frequent clear skies. As the month progresses, the air cools rapidly, and by November, average highs return to the 50s°F (10°C). November is the wettest month, with significant rainfall common, so waterproof gear becomes essential for any outdoor excursion.
Monthly Temperature Summary
The following table provides a detailed breakdown of average high and low temperatures for Ketchikan throughout the year, allowing for precise planning regardless of your travel dates.
