Yellowstone Park Snowfall Totals & Accumulation Averages

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).

Average total snowfall and days with fresh snow at Mammoth Hot Springs

Days		Inches	Centi­metres
8.7	January	11.5	29.2
9.4	February	11.5	29.2
7.0	March	10.9	27.7
5.5	April	7.8	19.8
1.2	May	1.7	4.3
0.1	June	0.3	0.8
0.3	September	0.6	1.5
2.8	October	4.7	11.9
7.5	November	9.9	25.1
10.2	December	12.6	32.0
52.7	Year	71.5	181.6

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.

Number of days per month and year on average at Mammoth Hot Springs with a total snowfall of at least 1, 3, 5 or 10 inches

1 inch 2.5 cm	3 inches 7.6 cm		5 inches 12.7 cm	10 inches 25.4 cm
4.4	1.0	January	0.3	0.1
5.0	0.8	February	0.2	0.0
3.8	1.0	March	0.4	0.1
3.7	0.7	April	0.2	0.0
0.8	0.2	May	0.1	0.0
0.1	0.0	June	0.0	0.0
0.2	0.1	September	0.0	0.0
1.5	0.4	October	0.2	0.0
4.2	1.2	November	0.6	0.0
5.1	1.2	December	0.2	0.0
28.8	6.6	Year	2.2	0.2

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.

Average total days per month and year at Mammoth Hot Springs with snow depth of at least 1, 3, 5 or 10 inches on the ground

1 inch 2.5 cm	3 inches 7.6 cm		5 inches 12.7 cm	10 inches 25.4 cm
30.9	29.9	January	25.1	6.7
26.8	24.8	February	21.0	9.4
18.7	14.9	March	12.5	5.6
6.1	2.3	April	1.1	0.5
0.9	0.2	May	0.1	0.0
0.1	0.0	June	0.0	0.0
0.2	0.1	September	0.0	0.0
2.9	1.1	October	0.5	0.2
16.0	8.3	November	3.1	0.6
27.9	20.9	December	13.9	2.1
130.5	102.5	Year	77.3	25.1