Photo: Finetooth · CC BY-SA 3.0Hardly any U.S. towns see fresher July days than Basin
The depth of winter brings overnight lows near 14°. The year swings widely: the coldest month’s nights and the warmest month’s afternoons are 64° apart. It is a dry place: less rain and snow fall here than on 92% of U.S. towns. The frost-free window for a garden runs roughly June 13 to September 5.
A year in Basin at a glance
Each month’s typical high and low, and what it brings.
What stands out about Basin’s climate
Compared with towns across the U.S., with Basin’s place in Montana beside it.
What a year in Basin feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 83 frost-free days a year
In half of years the last 32° night comes by June 13 and the first by September 5. Frost and day counts come from Butte Bert Mooney Airport, 24 miles away.
The 2023 USDA map puts Basin’s center in zone 4a: the coldest night of a typical winter, averaged over 1991–2020, reaches about −26°. 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 16 inches of rain a year
June is the wettest month and February the driest.
Rain + melted snow by month
Inches of water
Heating and cooling a home in Basin
99% of the work is heating, so the furnace matters far more than the air conditioner. Months averaging under 55° run from September through June.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Butte Bert Mooney Airport.
Living with Basin’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
83 frost-free days in zone 4a. The last frost comes by Jun 13 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 5.
Months with highs of 62–84° and lows of 40° or more: June, July and August. 2.4 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Basin from natural hazards, river flooding is the largest share (47%); heat waves, cold waves, winter storms and ice storms together are 20%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Basin and similar climates
TownRatings has no climate map of the towns around Basin yet.
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 Basin averaged 1.5° warmer than the 1900s. The biggest change is in January (+4.4°).
A bigger shift than in 58% 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 Basin compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Basin’s place among Montana’s.
Basin weather by month
Highs, lows and precipitation from NOAA’s grid at Basin’s center. 1991–2020 normals.
| Month | High | Low | Rain + melt | 30-yr range |
|---|---|---|---|---|
| January | 32° | 14° | 0.9" | 15° – 29° |
| February | 33° | 14° | 0.8" | 10° – 32° |
| March | 42° | 20° | 0.9" | 23° – 38° |
| April | 48° | 26° | 1.4" | 31° – 43° |
| May | 57° | 34° | 2.1" | 40° – 51° |
| June | 66° | 40° | 2.7" | 47° – 60° |
| July | 77° | 46° | 1.5" | 50° – 68° |
| August | 76° | 44° | 1.3" | 53° – 64° |
| September | 65° | 37° | 1.4" | 47° – 56° |
| October | 51° | 28° | 1.0" | 32° – 46° |
| November | 38° | 20° | 1.0" | 23° – 37° |
| December | 30° | 13° | 0.8" | 14° – 28° |
| Year | 51° | 28° | 15.9" |
How much a month can swing
A normal is an average. February swings the most: from 1991 to 2020 its average ranged from 10° to 32°. September is the most reliable, staying within 9°.
Where Basin’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 Basin’s center.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Butte Bert Mooney Airport, 24 miles from the town’s center, 590 ft lower; no station nearby passes every check; this is the nearest one in the same valley, flagged above.
- 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 Basin’s climate
What is the weather like in Basin?
A typical July afternoon reaches 77°, a January night drops to 14°. Colder January nights than 88% of U.S. towns; cooler July afternoons than 98% of U.S. towns.
How cold does it get in Basin in winter?
December nights average 13°. About 220 nights a year reach 32° or below and 31 reach 0° or below. In the coldest December of the last 30 years the month averaged 14°.
How hot does it get in Basin?
July, with a typical high of 77° and a low of 46°. About 8 days a year reach 90° (Butte Bert Mooney Airport).
When is the first and last frost in Basin?
In half of years the last spring frost (32°) comes by June 13 and the first fall frost by September 5, about 83 frost-free days, at Butte Bert Mooney Airport.
What growing zone is Basin in?
Zone 4a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −26°.
What is the best time of year to visit Basin?
By one simple rule (highs of 62–84° and lows of 40° or more), June, July and August. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Basin getting warmer?
Yes: 1991–2020 averaged 1.5° warmer than 1901–2000 on NOAA’s grid. A bigger shift than 58% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Basin.
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.