Weather in the Rocky Mountains can sometime be an adventure in and of itself, make sure to always check local weather before packing for your trip. Temperatures in this region can be unpredictable and change in an instant, but you can expect averages in the high 60s to low 70s degrees Fahrenheit (20 to 22 degrees Celsius) between early June and September.
Spring
Months: April, May, early June
You can expect moderate temperatures in lower elevations with averages around 50 degrees F (10 degrees C). Ski areas tend to remain open through March.
Summer
Months: Late June, July, August
Days can be sunny and hot, with temperatures reaching 80s and low 90s F (27 to 32 degrees C).
Nights tend to be much cooler with temperatures dipping down to 25-30 degrees F (-1 to 4 degrees C). Higher elevations, and in places like Yellowstone National Park and Glacier National Park, be prepared for a sudden snow or rain shower even in mid-summer. The higher the elevation, the cooler it gets.
Autumn
Months: September, October, early November
The Fall season comes with crisp daytime temperatures and frosty nights. Several ski resorts open in November, however weather can be unpredictable in the Fall. The days may be very nice, maybe even warm, however, the evenings cool off quite a bit. It is possible to get snow and/or rain. It’s recommended to wear layers and bring a heavy coat, hat, gloves and warm shoes and boots. Sunscreen, sunglasses, and lip balm are also useful items to have on hand during the daytime.
Winter
Months: Late November, December, January, March
Although the weather can be tough to endure at times, the stunning scenery and quietness that comes with the winter season makes this region one of the favorite seasons for the locals. Temperatures can average below freezing at about 25 degrees F (-3 C).