In a word, the weather in the Rocky Mountains is unpredictable. Temperatures are at best extreme, but you can expect temperatures to usually average in the high 60s to low 70s degrees Fahrenheit (20 to 22 degrees Celsius) between early June and September. Below we’ve outlined general temperatures throughout the year.
Moderate temperatures in the lower elevations. Ski areas open through March.
Days: Sunny and hot, with temperatures reaching 27 to 32 degrees C.
Nights: Can be cold: -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 colder it gets.
Crisp daytime temperatures. Frosty nights. Some ski resorts open in November. Weather can be unpredictable in autumn. The days may be very pleasant, maybe even warm, however, the evenings cool off quite a bit. It is possible to get snow and/or rain. We recommend wearing layers and it is highly recommended that you bring a heavy coat, hat, and gloves and warm shoes and boots. Sunscreen, sunglasses, and lip balm are also useful items to have on hand.
Temperatures can average below freezing.
When To Go
The summer season for visitors and tourist attractions starts in June and runs through September, with some operators opening later and closing a little earlier, depending on location- check the state tourism websites for more specific information on opening and closing dates.
The winter season typically runs from November through March, but again check with the relevant resort or State websites for specific operating dates and weather conditions