Polson, Montana climate: Normal weather by month, frost dates and records
Polson's normal year runs from 22°F December nights to 83°F July afternoons, with 15.0 inches of precipitation a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 7.9°C, December lows of −6°C, July highs of 28°C, 381 mm of precipitation a year.
- NOAA stationPolson
- Station IDUSC00246635
- Location47.67°N 114.19°W
- Elevation3,010 ft (917 m)
- Population5,631
On October 22, the normal high in Polson is 52°F and the normal low 34°F, and the chance of measurable rain or snow is 30%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Polson.
- Jan 33° 22°
- Feb 37° 22°
- Mar 47° 28°
- Apr 56° 34°
- May 66° 41°
- Jun 72° 47°
- Jul 83° 53°
- Aug 82° 53°
- Sep 71° 46°
- Oct 56° 36°
- Nov 41° 27°
- Dec 33° 22°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
What is the weather like in Polson each month?
July is the warmest month, with normal highs of 83°F; December the coldest, with normal lows of 22°F. The most precipitation falls in June (2.44 in), the least in August (0.76 in).
| Month | High | Low | Mean | Precip. | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|
| January | 33°F | 22°F | 27.7°F | 0.94 | 11 | <1 | 27 | 8 h 50 min |
| February | 37°F | 22°F | 29.4°F | 0.79 | 8 | <1 | 25 | 10 h 10 min |
| March | 47°F | 28°F | 37.8°F | 0.89 | 8 | <1 | 22 | 11 h 50 min |
| April | 56°F | 34°F | 44.9°F | 1.43 | 10 | <1 | 12 | 13 h 30 min |
| May | 66°F | 41°F | 53.3°F | 1.99 | 11 | <1 | 3 | 15 h 10 min |
| June | 72°F | 47°F | 59.8°F | 2.44 | 12 | <1 | <1 | 16 h |
| July | 83°F | 53°F | 68.0°F | 0.84 | 5 | 6 | <1 | 15 h 40 min |
| August | 82°F | 53°F | 67.3°F | 0.76 | 5 | 4 | <1 | 14 h 20 min |
| September | 71°F | 46°F | 58.3°F | 1.19 | 7 | <1 | 1 | 12 h 40 min |
| October | 56°F | 36°F | 45.6°F | 1.59 | 9 | <1 | 9 | 11 h |
| November | 41°F | 27°F | 34.3°F | 1.22 | 10 | <1 | 21 | 9 h 20 min |
| December | 33°F | 22°F | 27.6°F | 0.93 | 10 | <1 | 27 | 8 h 30 min |
| Year (annual) | 57°F | 36°F | 46.2°F | 15.01 | 104 | 11 | 147 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | 1°C | −6°C | −2.4°C | 24 mm |
| February | 3°C | −6°C | −1.4°C | 20 mm |
| March | 8°C | −2°C | 3.2°C | 23 mm |
| April | 13°C | 1°C | 7.2°C | 36 mm |
| May | 19°C | 5°C | 11.8°C | 51 mm |
| June | 22°C | 8°C | 15.4°C | 62 mm |
| July | 28°C | 12°C | 20.0°C | 21 mm |
| August | 28°C | 11°C | 19.6°C | 19 mm |
| September | 22°C | 8°C | 14.6°C | 30 mm |
| October | 13°C | 2°C | 7.6°C | 40 mm |
| November | 5°C | −3°C | 1.3°C | 31 mm |
| December | 1°C | −6°C | −2.4°C | 24 mm |
NOAA publishes no 1991-2020 snowfall normal for this station. The nearest record that keeps one, SKQ Dam (2 miles away), gets 34 inches of snow in a normal year; elevation and distance can change that.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00246635; annual normals. Wet days: 0.01 inch or more; 90°F days and freezing nights: NOAA's day counts. Daylight: sunrise to sunset on the 15th, computed from the latitude.
When is the best weather to visit Polson?
Normal highs sit between 65°F and 85°F in May, June, July, August and September. Of those, July has the fewest days with rain (5).
That is a measurement, not a recommendation: it counts the months whose normal afternoon high sits between 65°F and 85°F, where a light layer is enough by day.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00246635.
When is the last frost in Polson?
In Polson, the last spring frost (32°F) comes after May 10 in half of years and after May 26 in one year in ten; the first autumn frost comes before October 5 in half of years and before September 22 in one year in ten.
Frost-free in half of yearsFrost in 1 to 9 years out of 10Frost most years
- Last spring frost, half of years after
- May 101 year in 10 after May 26; 9 in 10 after April 27
- First autumn frost, half of years before
- October 51 year in 10 before September 22; 9 in 10 before October 19
NOAA puts the median frost-free season at 147 days, and the season without a hard freeze (28°F) at 171 days.
A hard freeze (28°F) comes after April 28 in half of springs and before October 16 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Polson in zone 6a in ZIP code 59860, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, Polson's NOAA station is in zone 6a: the coldest night of a typical year reaches −5°F (21 complete years).
Frost dates for every NOAA station in Montana · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00246635; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026; the station zone: ACIS daily lows, 1991-2020. A 10% date means one year in ten has a frost after it in spring or before it in autumn.
How hot and how cold does it get in Polson?
In a normal year in Polson, 11 days a year reach 90°F, 147 nights fall to 32°F or colder and 104 days bring measurable precipitation.
- Days at 90°F or more
- 11a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 147a normal year
- Days that stay below freezing
- 42high of 32°F or less
- Days with 0.01 inch of precipitation
- 104a normal year
The highest temperature in this station's record (since 1906) is 104°F, on July 16, 1919; the lowest is −30°F, on January 31, 1950.
The wettest calendar year on that record is 2010, with 21.61 in; the snowiest season is 1955–56, with 89.9 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00246635; records: ACIS (NOAA Regional Climate Centers), station USC00246635. Records use complete months only; a month missing more than three days is left out.
How sunny is Polson?
Over a year 71% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Polson, 3.7 kWh per square metre a day. July is the sunniest month (87%) and December the cloudiest (51%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 54% | 1.1 |
| February | 60% | 2.0 |
| March | 62% | 3.2 |
| April | 66% | 4.5 |
| May | 69% | 5.6 |
| June | 71% | 6.2 |
| July | 87% | 7.3 |
| August | 84% | 6.0 |
| September | 77% | 4.2 |
| October | 66% | 2.5 |
| November | 54% | 1.3 |
| December | 51% | 0.9 |
Source: NASA POWER solar climatology, 2001-2020 (CERES SYN1deg). Satellite-based, for the 1-degree cell (about 100 km across) around the station, so it describes the area rather than the airport.
How much heating and cooling does Polson need?
A normal year in Polson brings 7,130 heating degree days, 33% more than the median U.S. place (5,373), and 295 cooling degree days, 68% fewer than the median (908). Eight months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 1,881 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,156 | 0 |
| February | 995 | 0 |
| March | 845 | 0 |
| April | 603 | 0 |
| May | 368 | 5 |
| June | 177 | 21 |
| July | 39 | 134 |
| August | 47 | 120 |
| September | 217 | 15 |
| October | 600 | 0 |
| November | 921 | 0 |
| December | 1,161 | 0 |
| Year (annual) | 7,130 | 295 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00246635. A degree day is one degree of a day's mean temperature below 65°F (heating) or above it (cooling); utilities use them to estimate energy use.
How does Polson's climate compare?
Polson is warmer than 117 of the other 140 places with their own NOAA record in Montana, and wetter than 72. Across the 7,247 U.S. stations with normals, its annual mean of 46.2°F is warmer than 24%.
In the Köppen classification computed from these normals, Polson is Dfb: continental, no dry season, warm summer. What the classes mean.
Places with the most similar year elsewhere
Measured month by month on the normal high, low and precipitation, among places of 20,000 or more people in other states:
Source: NOAA NCEI 1991-2020 normals for every station PlainClimate covers. Similarity: the root-mean-square difference of the 36 monthly figures, precipitation weighted so an inch counts like 6°F.
Which places near Polson share this climate record?
8 places have no NOAA station with 1991-2020 normals of their own, and this station is the nearest full record. A place's own climate can differ from these figures, by several degrees where it sits much higher or lower than the station, nearer the coast, or inside a large city's heat; for the larger places the next nearest records are named with their yearly mean, so the spread around them is visible, and places of 50,000 or more have their own page with NOAA's gridded normals.
- Ronan, MT2,182 people · 11 mi S
- Pablo, MT1,808 people · 6 mi SE
- Finley Point, MT436 people · 7 mi NE
- Kerr, MT432 people · 0 mi E
- Kings Point, MT373 people · 7 mi N
- Jette, MT221 people · 3 mi N
- Rocky Point, MT127 people · 4 mi N
- Turtle Lake, MT61 people · 5 mi E
Source: Census Bureau 2024 Gazetteer (place centers) and Vintage 2024 population estimates. Distance and direction from the station to each place's center.
Questions about Polson's climate
What is the coldest month in Polson?
December, with a normal high of 33°F and a normal low of 22°F. The warmest is July (83°F by day, 53°F at night).
Does it snow in Polson?
Yes. NOAA publishes no 1991-2020 snowfall normal for Polson's NOAA station; the nearest record that keeps one, SKQ Dam (2 miles away), records 34 inches of snow in a normal year.
What is the rainiest month in Polson?
June, with 2.44 in of precipitation in a normal year; the driest is August with 0.76 in.
What plant hardiness zone is Polson in?
The USDA's 2023 map puts Polson in zone 6a in ZIP code 59860, the nearest ZIP area. By the same method at Polson's NOAA station, the coldest night of a typical year reaches −5°F (21 years, 1991-2020): zone 6a.
How late can frost come in Polson?
In half of years the last 32°F night comes after May 10; in one year in ten it comes after May 26. Waiting until May 26 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Montana climateThe statewide normals and every place in the state
- SKQ Dam, MT2 miles from this station, 45.2°F a year
- Bigfork (13 mi S), MT16 miles from this station, 46.8°F a year
- Swan Lake, MT24 miles from this station, 43.5°F a year
- St. Ignatius, MT25 miles from this station, 47.7°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made