Summer months in Jackson Hole are delightful and most aptly described as bluebird sky days sandwiched by cool mornings and evenings. We usually experience less than a dozen days in July and August where the daytime temperatures reach the upper 80s and low 90s. Night time temperatures can easily drop down into the 50s or colder, especially in June and September. Afternoon thundershowers are normal, and can be intense as they travel quickly across the valley.
Fall is absolutely beautiful in the valley, and is sometimes referred to as the ‘secret season’. With shorter sunny days and cooling temperatures, the cottonwood and aspen tree leaves become brilliant yellow. Autumn remains warm enough to enjoy many summertime activities, from fishing to hiking, all with fewer crowds. As the end of fall approaches, the pleasant weather can be interrupted by rain in the valley and snow in the mountains, which can unexpectedly delights skiers and snowboarders.
Jackson Hole has a reputation for experiencing snow every month of the year, keeping the mountain peaks snowy white. With cooling temperatures throughout the fall, winter arrives and the valley is blanketed in snow by December. Winter temperatures can easily range anywhere from subzero to 35 degrees Fahrenheit. The temperatures tend to be warmer when it is snowing and cloudy overnight. The coldest weather happens when the days are sunny with skies remaining clear overnight, creating an inversion. This is when the cold air is held down near the valley floor by a high pressure front. The good news is the temperature can be 10 to 20 degrees warmer at the top of the mountains, making for an epic day on the slopes!