Vail weather is pretty good on the whole, if not a little unpredictable. Whenever you venture into the Rocky Mountain highlands, conditions can change immediately. It's not uncommon for an afternoon thunderstorm to disrupt an otherwise sunny summer day, and skiers and snowboarders are encouraged to keep a pair of goggles handy at all times while on the mountain, as heavy snowstorms can come out of nowhere.
Winter: Winter is widely considered to be the best time to travel to Vail Colorado, as this is the prime skiing and snowboarding season. This part of the world enjoys around 300 sunny days a year on average, so blue skies and sunshine are plentiful even in the winter. You can also expect heavy snowstorms to move in at any given time, and they can drop a few feet of the fluffy stuff in just a few hours. It can get very cold in Vail during the winter. A winter daytime temperature in the 20s or low 30s is average, with the nights almost always being colder.
Spring: According to some, spring is the best time to visit Vail Colorado. Heavy snowfalls are known to pass through during this season, and the skiing and snowboarding are still quite good even on average days. Mostly gone is the threat of super-low temperatures, and since the daytime temps can easily move into the 40s or 50s with lots of sunshine, you can ski in shorts or a bikini on some days if you want to. One of the joys of spring skiing is having a cold one at one of the on-mountain lodges while you kick back and bask in the sun's warm rays.
Summer: There are some who will tell you that summer is absolutely the best time to travel to Vail Colorado. There are various reasons for this. The long summer activities list is one of them. Summer days in Vail can get hot. On average, the daytime temperature will be around 80 degrees. Things cool down considerably at night. It should be stressed that while rare, the threat of snow is not gone during the summer. Short-lived afternoon thunderstorms are very common in Vail during the summer season.
Fall: In all honesty, fall is most likely the worst time to visit Vail. That's not to say that this season doesn't have some merits, however. When the Aspen leaves turn gold, for example, the sightseeing is quite divine, and a variety of fun activities such as fishing and golfing can be enjoyed on many autumn days. In early fall, the daytime temperatures tend to be in the 40s and 50s on average, and decrease the closer that you get to winter.