Don't get it wrong—Yellowstone is a great spot to visit any season. It's less crowded and warmer in the spring and fall, though, so those are the best times to visit Yellowstone.
if you had to pick just one, September would be the best month to visit Yellowstone. After Labor Day (the first Monday in September), there are fewer people in Yellowstone.
Spring (April - May): Every road in Yellowstone National Park is typically accessible by the end of May. A few prominent roadways open as early as April.
Yellowstone has the best weather in the summer. Daytime temperatures of 70 degrees, longer sunny hours, and nice nighttime weather are all part of this season.
In Yellowstone, bison usually give birth in the middle of April. After hibernating all winter, bears are usually more busy around this time of year.
In a typical season, the best time to go to Yellowstone for fall colors is from the last week of September to the first week of October.
It gets busier in the weeks before Memorial Day in May, and less crowded after Labor Day in September. At this point in the year, the weather changes quickly. Spring has more rain than fall.
Best Time to Visit Yellowstone National Park for Photography