Sedan, MT climate
Sedan has chilly winters and pleasant summers. A typical July afternoon reaches 78°, a January night drops to 15°, and about 21 inches of snow falls in a normal winter.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in Sedan feels like
Winter
Spring
Summer
Fall
Sedan weather by month
Average highs, lows, rain and snow for every month, from NOAA’s 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | 30-yr range |
|---|---|---|---|---|---|---|
| January | 33° | 15° | 1.7" | 4.6" | 7 | 16° – 30° |
| February | 35° | 15° | 1.5" | 2.8" | 6 | 11° – 35° |
| March | 42° | 21° | 2.0" | 2.7" | 8 | 21° – 38° |
| April | 49° | 27° | 3.2" | 1.1" | 9 | 32° – 43° |
| May | 59° | 35° | 3.5" | 0.7" | 11 | 43° – 52° |
| June | 67° | 42° | 3.9" | 0.2" | 10 | 49° – 61° |
| July | 78° | 48° | 1.6" | 0 | 7 | 53° – 70° |
| August | 78° | 47° | 1.4" | 0 | 6 | 56° – 66° |
| September | 67° | 40° | 1.9" | 0 | 5 | 50° – 58° |
| October | 53° | 31° | 2.4" | 0.2" | 7 | 34° – 47° |
| November | 40° | 21° | 2.0" | 3.3" | 7 | 20° – 40° |
| December | 32° | 14° | 1.7" | 5.7" | 7 | 15° – 29° |
| Year | 53° | 30° | 26.7" | 21.3" | 90 |
“Wet days” have at least 0.01" of rain or melted snow. “Snow on ground” counts days with 1" or more. The 30-year range is the coldest and warmest that month’s average temperature got between 1991 and 2020.
Rain and snow in Sedan
Sedan gets 27 inches of rain and melted snow a year. June is the wettest month and August the driest. Rain or snow falls on about 90 days a year.
About 89 frost-free days a year
In half of years the last 32° night comes by June 8 and the first one by September 7. That leaves about 89 frost-free days for gardens, shorter than 99% of U.S. towns.
Heating and cooling a home in Sedan
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In Sedan, 99% of that work is heating and 1% is cooling, so the furnace matters far more than the air conditioner.
Degree days measure how far each day’s average temperature falls below or rises above 65°, added up over a year. Source: NOAA station normals.
How Sedan compares
Compared with every U.S. town and city on TownTapestry, each counted once.
Warmer than it used to be
The last 30 years in Sedan averaged 1.6° warmer than the 1900s. The biggest change is in January (+4.2°). The shift is larger than in 75% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at Sedan’s spot on NOAA’s grid
How much a month can swing
A normal is an average, and real years wander around it. February swings the most: between 1991 and 2020 its average temperature ranged from 11° to 35°. September is the most reliable, staying within 9°.
Common questions about Sedan’s climate
What is the coldest month in Sedan?
December, with a typical high of 32° and a low of 14°.
What is the hottest month in Sedan?
July, with a typical high of 78° and a low of 48°. About 3 days a year reach 90°.
How much snow does Sedan get?
About 21 inches in a normal winter, most of it in December.
When is the first frost in Sedan?
In half of years the first 32° night comes by September 7, and the last spring frost by June 8.
What is the rainiest month in Sedan?
June, with 3.9 inches of rain and melted snow. The year totals 27 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for Sedan itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Menard 3 Ne, MT (12 mi, snow) and Wilsall 8 Ene, MT (19 mi, frost, heat and degree days). Normals are 30-year averages, not a forecast. Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000.