Yellowstone Park Snowfall Totals & Accumulation Averages
This page pulls together information on when, how much and how often Mammoth Hot Springs in Yellowstone National Park, Wyoming has snow.
There are data and descriptions here of how many days it snows and the total amount of snowfall that Mammoth Hot Springs usually gets. There are also monthly and yearly counts of the days that Yellowstone Park normally has heavy snowstorms and deep snow accumulated on the ground. Plus there's information on when the Park can expect the first and last snowfalls of the season.
All the numbers are long-term historical averages based on weather data gathered from 1991 to 2020 at Mammoth Hot Springs, near Yellowstone Park's north entrance.
How Often it Snows in Yellowstone Park
This first table lists monthly and yearly totals for amount of snow and how many days it snows at least 0.1 inches (0.25 centimetres).
These averages don't show how much the snowfall in Yellowstone Park varies from year to year.
In December, for instance, one in four years totals over 17.2 inches of snow. Another 25 percent of years receive less than 7.8 inches for the month.
Similarly in January, fresh snowfall in the heaviest years amounts to over 14.4 inches, while the lightest years get less than 7.6 inches.
New snow for February ranges from over 14.7 inches in heavy snowfall years to under 5.6 inches in light years.
When Yellowstone Park Has Its First & Last Snowfalls
The first snowfall of autumn at Mammoth Hot Springs usually arrives in October. Occasionally September also gets a little snow.
The season's last snowfall most often happens in May. But in some years it stops snowing as early as April, while in others new snow lands as late as June.
Mammoth is normally free of snow every year during July and August.
How Many Snowstorms Yellowstone Park Gets
Most days of snowfall at Mammoth Hot Springs leave behind at least an inch of fresh snow. For seven days a year on average, the amount of new snow totals three inches or more.
Snowstorms of over five inches a day normally occur a couple times a year. But major blizzards that dump ten inches or more in one day are rare events that only happen about twice a decade.
How Much Snow Normally Accumulates in Yellowstone Park
Throughout most of winter, Mammoth Hot Springs has at least an inch of snow on the ground.
Typically on 25 days a year the snow covering this part of Yellowstone Park amounts to ten or more inches deep. On three of those days, the snowpack builds up to over 20 inches.
NOAA National Centers for Environmental Information (NCEI). Climate Normals.