Plains, MT climate
Plains has chilly winters and warm summers, with very little rain. A typical July afternoon reaches 88°, a January night drops to 21°, and about 15 inches of snow falls in a normal winter.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in Plains feels like
Winter
Spring
Summer
Fall
Plains 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 | 35° | 21° | 1.2" | 2.5" | 18 | 15° – 36° |
| February | 40° | 22° | 1.2" | 0.6" | 15 | 16° – 38° |
| March | 51° | 28° | 1.1" | 1.2" | 16 | 32° – 45° |
| April | 60° | 33° | 1.2" | 0.3" | 15 | 41° – 51° |
| May | 70° | 41° | 1.6" | 0 | 14 | 50° – 60° |
| June | 77° | 47° | 1.7" | 0 | 13 | 59° – 68° |
| July | 88° | 51° | 0.7" | 0 | 7 | 59° – 77° |
| August | 87° | 50° | 0.7" | 0 | 5 | 63° – 72° |
| September | 76° | 42° | 0.9" | 0 | 8 | 56° – 65° |
| October | 59° | 34° | 1.3" | 0.7" | 13 | 39° – 52° |
| November | 42° | 27° | 1.4" | 2.5" | 17 | 28° – 40° |
| December | 34° | 21° | 1.5" | 7.5" | 17 | 21° – 33° |
| Year | 60° | 35° | 14.4" | 15.3" | 158 |
“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 Plains
Plains gets 14 inches of rain and melted snow a year. June is the wettest month and August the driest. Rain or snow falls on about 158 days a year.
A year-round growing season
Heating and cooling a home in Plains
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In Plains, 97% of that work is heating and 3% 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 Plains 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 Plains averaged 1.1° warmer than the 1900s. The biggest change is in January (+3.5°). The shift is smaller than in 62% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at Plains’s spot on NOAA’s grid
How much a month can swing
A normal is an average, and real years wander around it. January swings the most: between 1991 and 2020 its average temperature ranged from 15° to 36°. August is the most reliable, staying within 9°.
Common questions about Plains’s climate
What is the coldest month in Plains?
January, with a typical high of 35° and a low of 21°.
What is the hottest month in Plains?
July, with a typical high of 88° and a low of 51°. About 29 days a year reach 90°.
How much snow does Plains get?
About 15 inches in a normal winter, most of it in December.
When is the first frost in Plains?
Frost is uncommon. Only 100% of years see a night at 32° or below.
What is the rainiest month in Plains?
June, with 1.7 inches of rain and melted snow. The year totals 14 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for Plains itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Thompson Falls Ph, MT (24 mi, snow) and Saint Regis 1 Ne, MT (14 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.