Denali National Park in July

June through August offers your best shot at seeing Denali's summit and navigating the park road. But each month brings trade-offs. June means 20 hours of daylight and peak wildlife activity, but also peak mosquitoes and muddy trails. July delivers the warmest weather — sometimes hitting 70°F — and wildflower blooms across the tundra. August brings fall colors and fewer bugs, but also the start of hunting season outside park boundaries. September offers northern lights and solitude, but most facilities close after Labor Day. Winter transforms the park into a cross-country skiing paradise, but you'll need serious cold-weather gear for temperatures hitting -40°F.