Swan Lake, MT climate
Swan Lake has chilly, snowy winters and pleasant summers. A typical July afternoon reaches 79°, a January night drops to 20°, and about 51 inches of snow falls in a normal winter.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in Swan Lake feels like
Winter
Spring
Summer
Fall
Swan Lake 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 | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 31° | 20° | 3.2" | 13.8" | 14 | 24 | 16° – 32° |
| February | 35° | 20° | 2.3" | 11.0" | 10 | 19 | 15° – 36° |
| March | 43° | 25° | 2.6" | 6.3" | 11 | 11 | 26° – 41° |
| April | 51° | 31° | 2.7" | 2.1" | 11 | 1 | 36° – 48° |
| May | 61° | 38° | 2.9" | 0.1" | 13 | 0 | 44° – 55° |
| June | 68° | 45° | 3.9" | 0 | 14 | 0 | 53° – 64° |
| July | 79° | 50° | 1.2" | 0 | 8 | 0 | 54° – 71° |
| August | 78° | 49° | 1.2" | 0 | 6 | 0 | 58° – 67° |
| September | 67° | 41° | 1.9" | 0 | 8 | 0 | 50° – 60° |
| October | 52° | 33° | 2.8" | 0.5" | 11 | 0 | 36° – 48° |
| November | 38° | 27° | 3.2" | 3.4" | 12 | 5 | 25° – 40° |
| December | 30° | 20° | 3.2" | 13.4" | 13 | 18 | 19° – 31° |
| Year | 53° | 33° | 31.2" | 50.6" | 129 | 79 |
“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 Swan Lake
Swan Lake gets 31 inches of rain and melted snow a year. June is the wettest month and August the driest. Rain or snow falls on about 129 days a year. Snow covers the ground about 79 days of the year.
About 121 frost-free days a year
In half of years the last 32° night comes by May 17 and the first one by September 19. That leaves about 121 frost-free days for gardens, shorter than 97% of U.S. towns.
Heating and cooling a home in Swan Lake
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In Swan Lake, 98% of that work is heating and 2% 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 Swan Lake 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 Swan Lake averaged 1.6° warmer than the 1900s. The biggest change is in January (+4.4°). The shift is larger than in 78% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at Swan Lake’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 15° to 36°. August is the most reliable, staying within 9°.
Common questions about Swan Lake’s climate
What is the coldest month in Swan Lake?
January, with a typical high of 31° and a low of 20°.
What is the hottest month in Swan Lake?
July, with a typical high of 79° and a low of 50°. About 16 days a year reach 90°.
How much snow does Swan Lake get?
About 51 inches in a normal winter, most of it in January.
When is the first frost in Swan Lake?
In half of years the first 32° night comes by September 19, and the last spring frost by May 17.
What is the rainiest month in Swan Lake?
June, with 3.9 inches of rain and melted snow. The year totals 31 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for Swan Lake itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Creston, MT (23 mi, snow) and Swan Lake, MT (2 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.