Mullan Snowfall Totals & Accumulation Averages
This page pulls together information on when, how much and how often Mullan, Idaho has snow.
There are data and descriptions here of how many days it snows and the total amount of snowfall that Mullan usually gets. There are also monthly and yearly counts of the days that Mullan normally has heavy snowstorms and deep snow accumulated on the ground. Plus there's information on when Mullan 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 1997 in Mullan, near the Lookout Pass ski area.
How Often it Snows in Mullan
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 Mullan varies from year to year.
In December, for instance, one in four years totals over 35.7 inches of snow. Another 25 percent of years receive at most 14 inches for the month.
Similarly in January, fresh snowfall in the heaviest years amounts to over 28 inches, while the lightest years get less than 11.6 inches.
New snow for February ranges from over 35.7 inches in heavy snowfall years to under 9.6 inches in light years.
When Mullan Has Its First & Last Snowfalls
The first snowfall of winter for Mullan usually arrives in November. Every few years, the snow starts flying in October. Although uncommon, September can also get a little snow.
The season's last snowfall most often happens in April. In one out of four years, it doesn't stop snowing until May.
Mullan is normally free of snow every year from June to August.
How Many Snowstorms Mullan Gets
Most days of snowfall in Mullan leave at least an inch of fresh snow. For 12 days a year on average, the amount of new snow totals three inches or more.
Snowstorms of over five inches a day normally occur five or six times annually. But major blizzards that dump ten inches or more in one day are rare events that don't happen every year.
How Much Snow Normally Accumulates in Mullan
For most of winter, Mullan has at least three inches of snow on the ground.
Snow mostly accumulates during January. Typically, on 20 days in January and another 12 in December and 15 in February, the snow covering Mullan gets to ten or more inches deep.
National Climatic Data Center. NOAA's 1981-2010 Climate Normals.