Precipitation in Bonner-West Riverside trails that of 88% of U.S. towns: 22 inches a year
Midwinter brings lows of about 18°. Summers stay cool: July afternoons here are cooler than in 79% of U.S. towns. Compared with 1901–2000, the average now sits 1.2° higher. Seedlings are safe outdoors from about May 10, with the first autumn frost due around October 1.
A year in Bonner-West Riverside at a glance
Each month’s typical high and low, and what it brings.
What stands out about Bonner-West Riverside’s climate
Compared with towns across the U.S., with Bonner-West Riverside’s place in Montana beside it.
What a year in Bonner-West Riverside feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 143 frost-free days a year
In half of years the last 32° night comes by May 10 and the first by October 1. Frost and day counts come from NOAA’s station at Missoula 2 Ne, MT, 4 miles from the town’s center, at about the same height.
The 2023 USDA map puts Bonner-West Riverside’s center in zone 5b: the coldest night of a typical winter, averaged over 1991–2020, reaches about −12°. 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 50 inches of snow a winter
Snow, measured at Missoula 2 Ne, MT, falls mostly in January and December. Precipitation (rain plus melted snow) adds up to 22 inches a year; June is the wettest month and August the driest. Rain or snow falls on about 132 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Bonner-West Riverside
95% 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 Missoula 2 Ne, MT.
Living with Bonner-West Riverside’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
143 frost-free days in zone 5b. The last frost comes by May 10 in half of years, so many gardeners wait a week or two past that to set out tomatoes. The first fall frost comes by Oct 1.
Months with highs of 62–84° and lows of 40° or more: June, July, August and September. 2.4 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Bonner-West Riverside from natural hazards, avalanches are the largest share (64%); heat waves, cold waves, winter storms and ice storms together are 10%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Bonner-West Riverside and similar climates
TownRatings has no climate map of the towns around Bonner-West Riverside yet.
Climates most like Bonner-West Riverside’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 |
|---|---|---|---|---|
| Bonner-West Riverside, MT | 18° | 82° | 22" | 50" |
| Gleneagle, CO | 14° | 84° | 21" | 55" |
| Sturgis, SD | 14° | 85° | 22" | 48" |
| Liberty Lake, WA | 25° | 84° | 22" | 45" |
| Doney Park, AZ | 17° | 86° | 16" | 52" |
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 Bonner-West Riverside averaged 1.2° warmer than the 1900s. The biggest change is in January (+3.7°).
A smaller shift than in 62% 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 Bonner-West Riverside compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Bonner-West Riverside’s place among Montana’s.
Bonner-West Riverside weather by month
Highs, lows and precipitation from NOAA’s grid at Bonner-West Riverside’s center; snow, wet days and snow on the ground from Missoula 2 Ne, MT. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 33° | 18° | 2.2" | 12.5" | 14 | 22 | 15° – 32° |
| February | 37° | 19° | 1.8" | 7.9" | 11 | 16 | 16° – 34° |
| March | 46° | 25° | 1.6" | 7.4" | 13 | 6 | 28° – 41° |
| April | 54° | 30° | 2.0" | 1.4" | 12 | 0 | 38° – 49° |
| May | 64° | 37° | 2.4" | 0.3" | 12 | 0 | 46° – 56° |
| June | 71° | 44° | 2.7" | 0.2" | 13 | 0 | 54° – 67° |
| July | 82° | 49° | 1.0" | 0.0" | 7 | 0 | 56° – 73° |
| August | 81° | 47° | 1.0" | 0.0" | 7 | 0 | 59° – 68° |
| September | 71° | 40° | 1.3" | 0.0" | 8 | 0 | 52° – 60° |
| October | 55° | 31° | 1.9" | 0.7" | 10 | 0 | 36° – 50° |
| November | 39° | 24° | 2.2" | 6.9" | 12 | 6 | 25° – 38° |
| December | 31° | 17° | 2.2" | 12.9" | 14 | 19 | 18° – 29° |
| Year | 55° | 32° | 22.2" | 50.2" | 132 | 70 |
How much a month can swing
A normal is an average. February swings the most: from 1991 to 2020 its average ranged from 16° to 34°. August is the most reliable, staying within 8°.
Where Bonner-West Riverside’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 Bonner-West Riverside’s center.
- Snow: Missoula 2 Ne, MT.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Missoula 2 Ne, MT, 4 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 Bonner-West Riverside’s climate
What is the weather like in Bonner-West Riverside?
A typical July afternoon reaches 82°, a January night drops to 18°, and about 50 inches of snow falls in a normal winter. Colder January nights than 71% of U.S. towns; cooler July afternoons than 79% of U.S. towns.
How cold does it get in Bonner-West Riverside in winter?
December nights average 17°. About 163 nights a year reach 32° or below and 5 reach 0° or below. In the coldest December of the last 30 years the month averaged 18°.
How much snow does Bonner-West Riverside get?
About 50 inches in a normal winter at Missoula 2 Ne, MT, most of it in January and December, with snow on the ground about 70 days a year.
How hot does it get in Bonner-West Riverside?
July, with a typical high of 82° and a low of 49°. About 22 days a year reach 90° (Missoula 2 Ne, MT).
When is the first and last frost in Bonner-West Riverside?
In half of years the last spring frost (32°) comes by May 10 and the first fall frost by October 1, about 143 frost-free days, at Missoula 2 Ne, MT.
What growing zone is Bonner-West Riverside in?
Zone 5b on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −12°.
What is the best time of year to visit Bonner-West Riverside?
By one simple rule (highs of 62–84° and lows of 40° or more), June, July, August and September. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Bonner-West Riverside getting warmer?
Yes: 1991–2020 averaged 1.2° warmer than 1901–2000 on NOAA’s grid. A smaller shift than 62% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Bonner-West Riverside.
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.