Norris, Montana climate: Normal weather by month, frost dates and records
Norris's normal year runs from 24°F December nights to 85°F July afternoons, with 18.4 inches of precipitation and 52 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 9.6°C, December lows of −5°C, July highs of 30°C, 466 mm of precipitation a year.
- NOAA stationNorris Madison Power House
- Station IDUSC00246157
- Location45.49°N 111.63°W
- Elevation4,745 ft (1,446 m)
- Population (census place)19
On October 14, the normal high in Norris is 61°F and the normal low 39°F, and the chance of measurable rain or snow is 23%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Norris.
- Jan 39° 24°
- Feb 42° 25°
- Mar 50° 30°
- Apr 57° 36°
- May 66° 43°
- Jun 75° 50°
- Jul 85° 57°
- Aug 85° 56°
- Sep 75° 49°
- Oct 60° 39°
- Nov 47° 30°
- Dec 38° 24°
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 Norris each month?
July is the warmest month, with normal highs of 85°F; December the coldest, with normal lows of 24°F. The most precipitation falls in June (3.17 in), the least in January (0.53 in).
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 39°F | 24°F | 31.3°F | 0.53 | 7.1 | 5 | <1 | 25 | 9 h |
| February | 42°F | 25°F | 33.0°F | 0.74 | 12.9 | 6 | <1 | 22 | 10 h 20 min |
| March | 50°F | 30°F | 39.9°F | 1.17 | 7.1 | 7 | <1 | 18 | 11 h 50 min |
| April | 57°F | 36°F | 46.2°F | 2.26 | 5.3 | 10 | <1 | 11 | 13 h 30 min |
| May | 66°F | 43°F | 54.8°F | 3.00 | 1.6 | 12 | <1 | 2 | 14 h 50 min |
| June | 75°F | 50°F | 62.5°F | 3.17 | 0.0 | 11 | 1 | <1 | 15 h 40 min |
| July | 85°F | 57°F | 71.3°F | 1.32 | 0.0 | 7 | 10 | <1 | 15 h 20 min |
| August | 85°F | 56°F | 70.5°F | 1.41 | 0.0 | 7 | 9 | <1 | 14 h 10 min |
| September | 75°F | 49°F | 61.9°F | 1.44 | 0.0 | 6 | 1 | 1 | 12 h 40 min |
| October | 60°F | 39°F | 49.5°F | 1.69 | 2.7 | 8 | <1 | 7 | 11 h |
| November | 47°F | 30°F | 38.4°F | 0.81 | 5.4 | 6 | <1 | 17 | 9 h 30 min |
| December | 38°F | 24°F | 30.8°F | 0.82 | 9.7 | 6 | <1 | 25 | 8 h 40 min |
| Year (annual) | 60°F | 39°F | 49.2°F | 18.36 | 51.8 | 90 | 21 | 127 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | 4°C | −5°C | −0.4°C | 13 mm | 18 cm |
| February | 5°C | −4°C | 0.6°C | 19 mm | 33 cm |
| March | 10°C | −1°C | 4.4°C | 30 mm | 18 cm |
| April | 14°C | 2°C | 7.9°C | 57 mm | 13 cm |
| May | 19°C | 6°C | 12.7°C | 76 mm | 4 cm |
| June | 24°C | 10°C | 16.9°C | 81 mm | 0 cm |
| July | 30°C | 14°C | 21.8°C | 34 mm | 0 cm |
| August | 29°C | 13°C | 21.4°C | 36 mm | 0 cm |
| September | 24°C | 9°C | 16.6°C | 37 mm | 0 cm |
| October | 16°C | 4°C | 9.7°C | 43 mm | 7 cm |
| November | 8°C | −1°C | 3.6°C | 21 mm | 14 cm |
| December | 3°C | −5°C | −0.7°C | 21 mm | 25 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00246157; 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 Norris?
Normal highs sit between 65°F and 85°F in May, June, August and September. Of those, September has the fewest days with rain (6).
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 USC00246157.
When is the last frost in Norris?
In Norris, the last spring frost (32°F) comes after April 30 in half of years and after May 14 in one year in ten; the first autumn frost comes before October 10 in half of years and before September 27 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
- April 301 year in 10 after May 14; 9 in 10 after April 15
- First autumn frost, half of years before
- October 101 year in 10 before September 27; 9 in 10 before October 27
NOAA puts the median frost-free season at 162 days, and the season without a hard freeze (28°F) at 188 days.
A hard freeze (28°F) comes after April 17 in half of springs and before October 22 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Norris in zone 5a in ZIP code 59745, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, Norris's NOAA station is in zone 6a: the coldest night of a typical year reaches −7°F (30 complete years); the map interpolates between stations and terrain, so the station and the ZIP area can differ by half a zone.
Frost dates for every NOAA station in Montana · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00246157; 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 Norris?
In a normal year in Norris, 21 days a year reach 90°F, 127 nights fall to 32°F or colder and 90 days bring measurable precipitation.
- Days at 90°F or more
- 21a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 127a normal year
- Days that stay below freezing
- 26high of 32°F or less
- Days with 0.01 inch of precipitation
- 90a normal year
- Days with 1 inch of snow or more
- 15a normal year
The highest temperature in this station's record (since 1907) is 102°F, on August 12, 1940; the lowest is −36°F, on February 9, 1933.
The wettest calendar year on that record is 1959, with 25.21 in; the snowiest season is 2018–19, with 130.9 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00246157; records: ACIS (NOAA Regional Climate Centers), station USC00246157. Records use complete months only; a month missing more than three days is left out.
How sunny is Norris?
Over a year 74% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Norris, 4.1 kWh per square metre a day. July is the sunniest month (84%) and December the cloudiest (63%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 69% | 1.7 |
| February | 73% | 2.8 |
| March | 70% | 3.8 |
| April | 66% | 4.8 |
| May | 67% | 5.6 |
| June | 75% | 6.6 |
| July | 84% | 7.2 |
| August | 83% | 6.1 |
| September | 79% | 4.6 |
| October | 69% | 2.9 |
| November | 66% | 1.8 |
| December | 63% | 1.3 |
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 Norris need?
A normal year in Norris brings 6,262 heating degree days, 17% more than the median U.S. place (5,373), and 523 cooling degree days, 42% 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 2,416 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,043 | 0 |
| February | 896 | 0 |
| March | 777 | 0 |
| April | 564 | 0 |
| May | 324 | 8 |
| June | 128 | 53 |
| July | 19 | 213 |
| August | 23 | 195 |
| September | 145 | 52 |
| October | 485 | 3 |
| November | 798 | 0 |
| December | 1,060 | 0 |
| Year (annual) | 6,262 | 523 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00246157. 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.
Has Norris been warmer than normal lately?
2025 averaged 51.1°F, 1.9°F above the 1991-2020 normal of 49.2°F. 3 of the 5 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. | Snow |
|---|---|---|---|---|
| 2021 | 50.3°F | +1.1°F | 19.91 | 40.7 |
| 2022 | 48.4°F | −0.8°F | 23.62 | 100.0 |
| 2023 | 49.1°F | −0.1°F | 23.64 | 90.7 |
| 2024 | 51.1°F | +1.9°F | 21.41 | 59.9 |
| 2025 | 51.1°F | +1.9°F | 20.00 | 55.3 |
Over 96 complete years from 1908 to 2025, the station's annual mean temperature rose at a fitted 3.7°F per century (+0.20°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: observed years: ACIS, station USC00246157; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Norris's climate compare?
Norris is warmer than 140 of the other 140 places with their own NOAA record in Montana, and wetter than 110. Across the 7,247 U.S. stations with normals, its annual mean of 49.2°F is warmer than 37%.
In the Köppen classification computed from these normals, Norris 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 Norris share this climate record?
3 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.
- McAllister, MT226 people · 6 mi SW
- Pony, MT101 people · 17 mi NW
- Harrison, MT96 people · 17 mi NW
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 Norris's climate
What is the coldest month in Norris?
December, with a normal high of 38°F and a normal low of 24°F. The warmest is July (85°F by day, 57°F at night).
Does it snow in Norris?
Yes: 52 inches in a normal year, falling on 18 days with 0.1 inch or more, the most in February (12.9 inches).
What is the rainiest month in Norris?
June, with 3.17 in of precipitation in a normal year; the driest is January with 0.53 in.
What plant hardiness zone is Norris in?
The USDA's 2023 map puts Norris in zone 5a in ZIP code 59745, the nearest ZIP area. By the same method at Norris's NOAA station, the coldest night of a typical year reaches −7°F (30 years, 1991-2020): zone 6a.
How late can frost come in Norris?
In half of years the last 32°F night comes after April 30; in one year in ten it comes after May 14. Waiting until May 14 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Montana climateThe statewide normals and every place in the state
- Ennis, MT11 miles from this station, 42.7°F a year
- Virginia City, MT21 miles from this station, 43.9°F a year
- Big Sky, MT21 miles from this station, 37.7°F a year
- Laurin (2 mi NE), MT24 miles from this station, 43.0°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made