Casper Snowfall Totals & Accumulation Averages
This page pulls together information on when, how much and how often Casper, Wyoming has snow.
There are data and descriptions here of how many days it snows and the total amount of snowfall that Casper usually gets. There are also monthly and yearly counts of the days that the city normally has heavy snowstorms and deep snow accumulated on the ground. Plus there's information on when Casper can expect the first and last snowfalls of the season.
All the numbers are long-term historical averages based on weather data gathered from 1981 to 2010 just outside Casper at the Natrona County International Airport.
How Often it Snows in Casper
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 Casper varies from year to year.
In December, for instance, one in four years totals over 12.6 inches of snow. Another 25 percent of years receive less than 5.2 inches for the month.
Similarly in January, fresh snowfall in the heaviest years amounts to over 12.8 inches, while the lightest years get less than 4.7 inches.
New snow for February ranges from over 12.6 inches in heavy snowfall years to under 6.2 inches in light years.
When Casper Has Its First & Last Snowfalls
The first snowfall of autumn for Casper usually arrives in October. Once every three or four years it starts snowing in September.
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.
Casper is normally free of snow every year in July and August.
How Many Snowstorms Casper Gets
About half the days of snowfall in Casper leave just a skiff, amounting to less than an inch of fresh snow. For 23 days a year on average, the amount of new snow totals at least an inch.
Snowstorms of over five inches a day normally occur two or three times a year. But major blizzards that dump ten inches or more in one day are uncommon events that don't appear every year.
How Much Snow Normally Accumulates in Casper
For half of winter days Casper has at least an inch of snow on the ground.
Snow mostly accumulates during December and January. Typically, on four days in those months plus another couple of days in November and February, the snow covering Casper gets to five or more inches deep.
National Climatic Data Center. NOAA's 1981-2010 Climate Normals.