Weather is a central concern to those planning to visit Kobuk Valley National Park at any time of year. Summer temperatures are usually in the mid 60°'s F, with 70's to 80° for highs. Some days in July may reach 85° F. Average January lows are -8°F with possible lows of -50°F. Annual averages are not always good guidelines, however. In summer, visitors can see snow, near freezing temperatures, and long periods of clouds, wind, and rain.
Winds average 5 to 10 mph, but 20 to 30 mph winds may accompany storms and produce lower wind chill factors. Any time of year, exposure and hypothermia are real threats to travelers. Be prepared - everyone should plan on meeting all of their own survival needs while traveling in the park. For backcountry hiking and camping, wear plenty of warm clothing, dress in layers, and use high quality rain gear. Wear sturdy hiking boots and bring knee-high rubber/neoprene boots for wet terrain.
Summer days are long and energized with sunlight. The sun does not set between June 3rd and July 9th. Some people may find it hard to sleep with all the sunshine in the summer, especially in a bright colored tent. It may help to bring a dark-colored eye mask to make sleeping easier when it is noontime bright at 2 am.
Winter days are short. Although beautiful twilight lasts hours each day, the sun is above the horizon only 1 ½ hours on December 21st. Northern lights are active year round, but are best seen during high solar activity on the darkest nights of winter.
To stay warm, layers of polypropylene, fleece, wool or fur are good options. Outerwear insulated with synthetic materials can be helpful. Down works well as long as it doesn't get soaking wet. To stay dry, a breathable rain jacket and rain pants are important, especially if you are going to be active. If you are doing less strenuous activities, nonbreathable raingear is suitable. Avoid wearing clothing made of cotton - it absorbs and holds moisture for a long time, which substantially increases your risk of hypothermia.