Chinook, MT Climate: Temperature & Rain by Month
Average temperature and precipitation from NOAA NCEI 1991–2020 normals →, with a derived climate comfort score
30-year climate normals (1991-2020) from Chinook's primary NOAA station, CHINOOK - 2 stations mapped to the area.
The climate verdict for Chinook
Dryness leads the climate profile for Chinook, Montana, with 13.4 inches of precipitation a year. NOAA records an annual average of 42°F. At 40/100 (moderate) the climate comfort score falls in the bottom third of the station-mapped U.S. score corpus, exceeding only 6% of scores.
- 42°F
- annual average temperature (NOAA normal)
- 40/100
- comfort score, above 6% of station-mapped location scores
- 13.4"
- yearly precipitation total
- 132 days
- growing season, frost-free days
Chinook: NOAA 1991-2020 normals describe a typical year, not a forecast. Method: /methodology.
Normals record plate
Sheet USC00241722 · Chinook, MT 42°F mean · 13.4" precip
TEMP-COOL · RANK-COOL · PHOTO-FINISH · PRCP-DRY · SWING-WIDE · COMF-LOW · LOAD-HEAT · STN-MULTI · BOOK-FULL
- TEMP-COOL 42°F
- RANK-COOL #686
- PHOTO-FINISH ≈ Grassy Butte
- PRCP-DRY 13.4"
- SWING-WIDE 53°F
- COMF-LOW 40/100
- LOAD-HEAT 8,571 HDD
- STN-MULTI USC00241722
- BOOK-FULL 6/6 fields
Nearest mean-temperature peer: Grassy Butte, ND (+ 0 °F mean)
Instrument codes from this station's NOAA 1991–2020 normals, mean temperature, corpus warmth rank, photo-finish peer station, precipitation band, seasonal swing, comfort composite, degree-day load, and field book, not a livability rating.
Mean-temperature neighbourhood
Nationwide NOAA normal poles and nearest peers, not a reprint of every MT station list.
- Hot Taylor, ND 43°F
- Chinook (this station) 42°F
- Cold Ellsworth, WI 42°F
- Near Grassy Butte, ND 42°F
- Near Big Falls Hydro, WI 42°F
Chinook sits in Montana, the #6 coldest U.S. state at 43.4°F statewide annual average - see all 50 coldest states ranked by NOAA normals
Climate Living Index · Chinook
Chinook: 14/100 · grade F
Chinook publishes 4 of 6 Living Index dimensions (NOAA annual/seasonal normals · NOAA daily multivariate normals); 2 missing weights rescale to 100.
PlainClimate-derived for Chinook, not an official NOAA rating. Rankings still use Comfort Score 40/100 (separate formula). Breakpoints and limits.
| Dimension | Station value | Score |
|---|---|---|
| Precipitation balance | 13.4 in · 21.6 from 35 in | 23/100 · F |
| Normal heat + freeze calendar | 200 calendar days | 14/100 · F |
| Frost-free season | 132 days/year | 13/100 · F |
| Annual temperature balance | 42.4°F · 25.1° from 67.5°F | 10/100 · F |
Chinook · 2026-08-04 · NOAA NCEI Climate Normals · method · Comfort Score method.
Chinook's normals sit in a dry climate class: BSk
Precipitation is low relative to temperature but above true desert thresholds: cold semi-arid steppe (BSk). Class BSk is the Peel et al. (2007) label for this station's monthly mean temperature and precipitation normals: dry (arid or semi-arid), specifically cold semi-arid steppe.
- Köppen code
- BSk
- Group
- Dry (arid or semi-arid)
- Warmest month
- 69.0°F
- Coldest month
- 15.7°F
Source: official public datasets monthly normals (1991–2020) at the city’s primary station. This is a station classification, not a mapped regional consensus.
National standing · heating-led station
Where Chinook sits across the climate record
Three NOAA fields for Chinook's primary station, temperature, precipitation, and seasonal swing, are ranked against every station-mapped normal that carries the same field.
- Annual temperature
- Cooler than 90%
- Among 6,861 stations, Chinook sits in the cooler third of annual means.
- Annual precipitation
- Drier than 86%
- Chinook's annual total ranks in the drier third of 6,352 measured normals.
- Seasonal temperature swing
- Wider than 89%
- Warmest-to-coldest month gap for Chinook is large versus 6,861 complete station-years.
How Chinook compares across U.S. station-mapped locations
Chinook's comfort score vs. all station-mapped locations
PlainClimate composite comfort index (1–100), NOAA 1991–2020 normals
40 6th percentile score exceeds 6% of 6,189 station-mapped location scores
- 0–10: 0 station-mapped locations (0%). Below this entry.
- 10–20: 0 station-mapped locations (0%). Below this entry.
- 20–30: 96 station-mapped locations (2%). Below this entry.
- 30–40: 280 station-mapped locations (5%). Below this entry.
- 40–50: 1,113 station-mapped locations (18%). This entry sits in this band.
- 50–60: 1,329 station-mapped locations (21%). Above this entry.
- 60–70: 1,236 station-mapped locations (20%). Above this entry.
- 70–80: 650 station-mapped locations (11%). Above this entry.
- 80–90: 921 station-mapped locations (15%). Above this entry.
- 90–100: 564 station-mapped locations (9%). Above this entry.
Source NOAA U.S. Climate Normals, PlainClimate comfort index · 1991–2020
Chinook's measured station temperature trend
MethodologyAcross 66 complete annual observations from 1917 to 2024, CHINOOK warmed at a fitted rate of 0.10°C per decade. The line shows the fitted change relative to its first year, not raw year-to-year temperatures or a forecast.
- Chinook primary station fitted change +0.10 °C/decade
Monthly Temperatures
Average daily high and low temperatures by month
| Month | Avg High | Avg Low | Mean | Precip | Freeze Days | 90°F+ Days |
|---|---|---|---|---|---|---|
| January | 27°F (-3°C) | 4°F (-15°C) | 16°F (-9°C) | 0.5" | 30.0 | 0.0 |
| February | 31°F (0°C) | 7°F (-14°C) | 19°F (-7°C) | 0.4" | 27.8 | 0.0 |
| March | 43°F (6°C) | 18°F (-8°C) | 30°F (-1°C) | 0.6" | 29.1 | 0.0 |
| April | 57°F (14°C) | 29°F (-1°C) | 43°F (6°C) | 1.0" | 19.7 | 0.0 |
| May | 67°F (19°C) | 40°F (4°C) | 54°F (12°C) | 2.4" | 6.2 | 0.5 |
| June | 75°F (24°C) | 49°F (10°C) | 62°F (17°C) | 2.9" | 0.1 | 2.1 |
| July | 84°F (29°C) | 54°F (12°C) | 69°F (21°C) | 1.6" | 0.0 | 9.9 |
| August | 83°F (29°C) | 52°F (11°C) | 68°F (20°C) | 1.1" | 0.0 | 9.7 |
| September | 72°F (22°C) | 41°F (5°C) | 57°F (14°C) | 1.0" | 3.1 | 2.0 |
| October | 57°F (14°C) | 29°F (-2°C) | 43°F (6°C) | 0.9" | 20.3 | 0.0 |
| November | 41°F (5°C) | 17°F (-8°C) | 29°F (-2°C) | 0.7" | 27.9 | 0.0 |
| December | 31°F (-1°C) | 8°F (-14°C) | 19°F (-7°C) | 0.4" | 30.7 | 0.0 |
The year, day by day
Summer here tops out rather than builds: the warmest normal high is 87°F around July 28, short of 90°F on every date, while 200 dates carry a normal low at or below freezing, the coldest 4°F near January 7.
The freezing stretch
The normal low stays at or below 32°F into April 25, then returns to freezing around October 9, covering 200 dates in all.
Derived from the normal daily minimum. This is a different measure from the 50%-probability frost dates shown elsewhere on this page, which come from NOAA’s frost product.
Where the wet dates fall
The likeliest wet date is June 10, when 37% of years recorded at least a hundredth of an inch. The driest is January 29 at 14%. Summed across the calendar, that is about 77 wet dates a year.
The widest day
July 26 carries the biggest normal gap between afternoon and dawn, 32°F between the normal high and the normal low.
Look up any date
Any date's 1991–2020 normal for Chinook.
Where Chinook Stands Nationally
Winters bite deep and often: the normal nightly low dips to freezing or below on around 200 nights a year, placing this among the most frost-prone tenth of ranked stations.
A drier-than-most normal water year — around 13 inches, below what four out of five ranked stations collect.
Chinook earns 2 nationally notable standings (outer quintiles) against 6,860 NOAA 1991–2020 normals stations; only those extremes render.
Monthly Precipitation
Average monthly rainfall
4.8 days with precipitation
4.6 days with precipitation
4.6 days with precipitation
6.4 days with precipitation
9.7 days with precipitation
11.4 days with precipitation
7.2 days with precipitation
5.4 days with precipitation
6.5 days with precipitation
5.5 days with precipitation
5.5 days with precipitation
4.9 days with precipitation
Chinook runs a summer-peaked wet season
42% of Chinook's yearly precipitation falls in June, July and August alone, against the 25% an evenly spread year would give those three months. The wettest month is June at 2.9", on a wide 53.3°F gap between its warmest and coldest month. Warm-season convection and, across the Southwest, the North American monsoon produce this shape: rain arrives in short heavy bursts during the hottest part of the year rather than as long cool-season soaking.
- Wettest three months: June, May, July, taking 51% of the annual total between them.
- Driest month: February at 0.4".
- Winter share: 9% falls in December, January and February.
Shares are computed from this station's own 1991-2020 monthly precipitation normals. A summer-peaked label means the June-August share reaches 35%; it describes timing across an average year, not any single season, and says nothing about how heavy an individual storm can be.
Chinook is dry, and what does fall arrives gently
Only about 77 days a year record measurable precipitation here, 21% of the calendar, and they carry 13.4" between them. At roughly 0.18 inches on an average wet day, this is not the damp drizzle of a marine climate; it is an arid record in which precipitation is both uncommon and light when it appears.
The wettest month by count is June at about 11 wet days; the driest is February at about 5.
A low per-event average in a dry record is a statement about typical days only. Arid regions can still take a large share of a year's total from a single convective storm, which a normal cannot show.
A wet day is one recording at least 0.01 inches. These are 1991-2020 normals: they describe an average year, not the extremes within it.
Frost Dates & Growing Season
First Fall Freeze
September 23
50% probability date
Last Spring Freeze
May 14
50% probability date
Growing Season
132 days
Heating & Cooling Degree Days
Annual totals indicate energy demand for heating and cooling
Heating Degree Days
8,571
Higher = more heating needed
Cooling Degree Days
351
Higher = more cooling needed
Warmest Month
July
Coldest Month
January
Nationwide similar cities
Other rankable U.S. places outside MT closest to Chinook on two NOAA annual-normal axes (mean temperature and annual precipitation). Chip rows use distinct link sets.
Closest by average temperature
Nearest out-of-state peers by annual mean temperature (42°F here).
- Astoria, SD 42°F · 0.0°F off
- Ridgeland, WI 42°F · 0.0°F off
- Ruth, NV 42°F · 0.0°F off
- Soda Springs, ID 42°F · 0.0°F off
Closest by annual precipitation
Nearest out-of-state peers by annual precipitation (13.4" here), excluding temperature-peer places.
- Briggsdale, CO 13.4" · 0.0" off
- Glendo, WY 13.4" · 0.0" off
- Stockton, CA 13.4" · 0.0" off
- Weiser, ID 13.4" · 0.0" off
Scarce-water calendar
Where Chinook's limited precipitation lands
heating led · dry · mid swing
Chinook's energy balance leans toward cold weather: 8,571 annual heating degree days against 351 for cooling. Its 53.3°F seasonal range still makes the monthly rows more useful than the annual average alone.
Only about 132 days are frost-free in a normal year. That short interval is consistent with the cold-season signal, but the measure does not predict the exact first or last freeze in any one year.
July and January mark the typical warm and cold ends of the calendar in Chinook's middle-range seasonal profile. The measured spread is 53.3°F. The annual average is 42°F. Neither the annual mean nor one extreme month represents the full calendar on its own.
Chinook's cold-season load does not imply a wet climate. Annual precipitation is 13.4 inches, which places the station in PlainClimate's dry range. Snowfall is not added to the interpretation because its annual value is missing. The snowfall and rainfall fields should be read separately rather than inferred from temperature.
Chinook wettest normal
June
June concentrates the scarce annual total (13.4 inches).
Chinook driest normal
February
February is typically driest; arid stations are defined by when water is absent, not by a four-season grid.
Questions about Chinook's climate
How dry is Chinook? ▼
How cold does Chinook get in winter? ▼
How much energy does heating and cooling require in Chinook? ▼
Data Sources
Data source: NOAA U.S. Climate Normals v1.0.1 (1991-2020). All figures on this page are from Chinook's primary station: CHINOOK (USC00241722). 2 NOAA stations are mapped to the Chinook area; the primary station's record is used for consistency. For informational purposes only.
Place identity: U.S. Census Bureau 2024 Gazetteer places. The 2024 Census Gazetteer identifies the exact name-and-state match as an incorporated place (GEOID 3014575). Match rule for Chinook: exact normalized name + state only, no fuzzy expansion, so nearby differently spelled facilities stay unmatched.
On this page every temperature, precipitation, and derived score for Chinook comes from its primary NOAA station record. No figure on this page is typed in by an editor - each value is rendered from NOAA 1991-2020 U.S. Climate Normals. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of 1991–2020 normals.