Photo: J.B. Chandler · CC BY-SA 3.0Hardly any U.S. towns see harsher January nights than Chinook
On a normal July day the thermometer tops out near 85°. Precipitation is light here, less than falls on 95% of U.S. towns. Decade by decade the climate has edged up, 1.3° above 1901–2000. Keep the boiler serviced for the months from October to April, which average under 50°.
A year in Chinook at a glance
Each month’s typical high and low, and what it brings.
What stands out about Chinook’s climate
Compared with towns across the U.S., with Chinook’s place in Montana beside it.
What a year in Chinook feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 130 frost-free days a year
In half of years the last 32° night comes by May 14 and the first by September 23. Frost and day counts come from NOAA’s station at Chinook, MT, 0.2 miles from the town’s center, at about the same height.
The 2023 USDA map puts Chinook’s center in zone 3b: the coldest night of a typical winter, averaged over 1991–2020, reaches about −31°. Plant labels use the zone; frost dates tell you when to plant.
Freezing nights by month
Average nights at or below 32°
90° days by month
Average days at 90° or more
About 41 inches of snow a winter
Snow, measured at Havre City Co Airport, falls mostly in January and December. Precipitation (rain plus melted snow) adds up to 13 inches a year; June is the wettest month and December the driest. Rain or snow falls on about 90 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Chinook
96% of the work is heating, so the furnace matters far more than the air conditioner. Months averaging under 55° run from October through May.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Chinook, MT.
Living with Chinook’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
130 frost-free days in zone 3b. The last frost comes by May 14 in half of years, so many gardeners wait a week or two past that to set out tomatoes. The first fall frost comes by Sep 23.
Months with highs of 62–84° and lows of 40° or more: May, June and September. 0.1 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Chinook from natural hazards, river flooding is the largest share (51%); heat waves, cold waves, winter storms and ice storms together are 42%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Chinook and similar climates
TownRatings has no climate map of the towns around Chinook yet.
Climates most like Chinook’s, farther away
TownRatings’ own comparison of NOAA 1991–2020 normals, not a NOAA product: places of 5,000+ at least 150 miles away, one per state, closest on January low, July high, precipitation and snow.
| Town | Jan. low | July high | Precip. | Snow |
|---|---|---|---|---|
| Chinook, MT | 6° | 85° | 13" | 41" |
| Watford City, ND | 4° | 84° | 16" | 50" |
| Gypsum, CO | 11° | 86° | 14" | 39" |
| Green River, WY | 9° | 87° | 9" | 39" |
| Taos, NM | 11° | 84° | 13" | 28" |
Temperatures and precipitation come from NOAA’s 5 km grid; snow and day counts from the stations named on this page.
Warmer than it used to be
The last 30 years in Chinook averaged 1.3° warmer than the 1900s. The biggest change is in January (+4.6°).
A smaller shift than in 55% of U.S. towns.
Change by month
The two periods overlap (1991–2000 is in both), which makes the gap a little smaller than it would be between separate periods.
How Chinook compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Chinook’s place among Montana’s.
Chinook weather by month
Highs, lows and precipitation from NOAA’s grid at Chinook’s center; snow, wet days and snow on the ground from Havre City Co Airport. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 27° | 6° | 0.5" | 9.0" | 7 | 21 | 0° – 32° |
| February | 32° | 9° | 0.4" | 6.9" | 6 | 13 | −5° – 35° |
| March | 44° | 20° | 0.6" | 5.2" | 6 | 9 | 13° – 41° |
| April | 58° | 30° | 1.0" | 2.7" | 8 | 2 | 36° – 48° |
| May | 68° | 40° | 2.1" | 0.4" | 11 | 0 | 50° – 61° |
| June | 76° | 49° | 2.9" | 0.0" | 12 | 0 | 60° – 66° |
| July | 85° | 54° | 1.5" | 0.0" | 8 | 0 | 61° – 76° |
| August | 84° | 52° | 1.1" | 0.0" | 7 | 0 | 64° – 73° |
| September | 73° | 42° | 1.2" | 0.4" | 7 | 0 | 54° – 64° |
| October | 58° | 30° | 0.8" | 2.0" | 7 | 1 | 37° – 50° |
| November | 42° | 19° | 0.6" | 6.2" | 6 | 7 | 18° – 40° |
| December | 31° | 9° | 0.4" | 8.2" | 6 | 13 | 4° – 32° |
| Year | 56° | 30° | 13.2" | 41.0" | 90 | 67 |
How much a month can swing
A normal is an average. February swings the most: from 1991 to 2020 its average ranged from -5° to 35°. June is the most reliable, staying within 7°.
Where Chinook’s numbers come from
Normals are 30-year averages, not a forecast. How TownRatings reads climate data →
- Temperatures and precipitation: NOAA’s gridded 1991–2020 normals for the 5 km cell at Chinook’s center.
- Snow: Havre City Co Airport.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Chinook, MT, 0.2 miles from the town’s center, at about the same height; the nearest station that passes our checks for distance, height and agreement with the grid.
- Growing zone: USDA Plant Hardiness Zone Map, 2023. USDA Agricultural Research Service and PRISM Group, Oregon State University, prism.oregonstate.edu/phzm, accessed 8 Oct 2026.
- Then and now: NOAA’s gridded normals for 1901–2000 at the same cell.
- Storms and extremes: FEMA National Risk Index (expected annual losses to buildings).
Common questions about Chinook’s climate
What is the weather like in Chinook?
A typical July afternoon reaches 85°, a January night drops to 6°, and about 41 inches of snow falls in a normal winter. Colder January nights than 97% of U.S. towns; hotter July afternoons than 51% of U.S. towns.
How cold does it get in Chinook in winter?
January nights average 6°. About 195 nights a year reach 32° or below and 36 reach 0° or below. In the coldest January of the last 30 years the month averaged 0°.
How much snow does Chinook get?
About 41 inches in a normal winter at Havre City Co Airport, most of it in January and December, with snow on the ground about 67 days a year.
How hot does it get in Chinook?
July, with a typical high of 85° and a low of 54°. About 24 days a year reach 90° and 1 reach 100° (Chinook, MT).
When is the first and last frost in Chinook?
In half of years the last spring frost (32°) comes by May 14 and the first fall frost by September 23, about 130 frost-free days, at Chinook, MT.
What growing zone is Chinook in?
Zone 3b on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −31°.
What is the best time of year to visit Chinook?
By one simple rule (highs of 62–84° and lows of 40° or more), May, June and September. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Chinook getting warmer?
Yes: 1991–2020 averaged 1.3° warmer than 1901–2000 on NOAA’s grid. A smaller shift than 55% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Chinook.
Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000; USDA/PRISM 2023 hardiness zones; FEMA National Risk Index. Today’s forecast: National Weather Service.