Hardly any U.S. towns collect less precipitation than Simms: 13 inches a year
Sunny July days climb to about 83°. The wettest month is June; the driest is January. Its January nights bite harder than in 85% of U.S. towns. Central heating does most of its work from October to April, in months below 50° on average.
A year in Simms at a glance
Each month’s typical high and low, and what it brings.
What stands out about Simms’ climate
Compared with towns across the U.S., with Simms’ place in Montana beside it.
What a year in Simms feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 135 frost-free days a year
In half of years the last 32° night comes by May 13 and the first by September 27. Frost and day counts come from NOAA’s station at Fairfield, MT, 9 miles from the town’s center, 390 ft higher.
The 2023 USDA map puts Simms’ 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 46 inches of snow a winter
Snow, measured at Simms 1 Ne, MT, is heaviest from March through April, about 7 inches a month. Precipitation (rain plus melted snow) adds up to 13 inches a year; June is the wettest month and January the driest. Rain or snow falls on about 85 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Simms
97% 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 Fairfield, MT.
Living with Simms’ climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
135 frost-free days in zone 4a. The last frost comes by May 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 27.
Months with highs of 62–84° and lows of 40° or more: June, July, August and September. 1.8 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Simms from natural hazards, river flooding is the largest share (45%); heat waves, cold waves, winter storms and ice storms together are 37%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Simms and similar climates
TownRatings has no climate map of the towns around Simms yet.
Climates most like Simms’, 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 |
|---|---|---|---|---|
| Simms, MT | 15° | 83° | 13" | 46" |
| Cody, WY | 14° | 85° | 11" | 45" |
| Los Alamos, NM | 19° | 85° | 15" | 42" |
| Doney Park, AZ | 17° | 86° | 16" | 52" |
| Rexburg, ID | 12° | 84° | 13" | 70" |
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 Simms averaged 1.3° warmer than the 1900s. The biggest change is in January (+5.1°).
A smaller shift than in 57% 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 Simms compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Simms’ place among Montana’s.
Simms weather by month
Highs, lows and precipitation from NOAA’s grid at Simms’ center; snow, wet days and snow on the ground from Simms 1 Ne, MT. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 37° | 15° | 0.4" | 6.5" | 7 | 13 | 13° – 37° |
| February | 38° | 16° | 0.4" | 6.2" | 6 | 11 | 1° – 39° |
| March | 47° | 22° | 0.6" | 7.3" | 7 | 7 | 18° – 44° |
| April | 55° | 30° | 1.5" | 7.4" | 9 | 4 | 37° – 47° |
| May | 65° | 38° | 2.1" | 1.4" | 10 | 1 | 47° – 56° |
| June | 73° | 46° | 2.6" | 0.6" | 11 | 0 | 56° – 65° |
| July | 83° | 51° | 1.1" | 0.0" | 7 | 0 | 57° – 74° |
| August | 82° | 49° | 1.0" | 0.3" | 6 | 0 | 60° – 70° |
| September | 71° | 41° | 1.2" | 0.2" | 6 | 0 | 52° – 63° |
| October | 57° | 32° | 0.8" | 3.2" | 6 | 2 | 36° – 52° |
| November | 44° | 24° | 0.5" | 6.4" | 6 | 7 | 23° – 44° |
| December | 36° | 17° | 0.4" | 6.4" | 6 | 10 | 14° – 36° |
| Year | 57° | 32° | 12.6" | 45.9" | 85 | 55 |
How much a month can swing
A normal is an average. February swings the most: from 1991 to 2020 its average ranged from 1° to 39°. June is the most reliable, staying within 9°.
Where Simms’ 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 Simms’ center.
- Snow: Simms 1 Ne, MT (NOAA station in town).
- Frost, freezing nights, 90° and 100° days, heating and cooling: Fairfield, MT, 9 miles from the town’s center, 390 ft higher; 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 Simms’ climate
What is the weather like in Simms?
A typical July afternoon reaches 83°, a January night drops to 15°, and about 46 inches of snow falls in a normal winter. Colder January nights than 85% of U.S. towns; cooler July afternoons than 70% of U.S. towns.
How cold does it get in Simms in winter?
January nights average 15°. About 160 nights a year reach 32° or below and 17 reach 0° or below. In the coldest January of the last 30 years the month averaged 13°.
How much snow does Simms get?
About 46 inches in a normal winter at Simms 1 Ne, MT, heaviest from March through April, about 7 inches a month, with snow on the ground about 55 days a year.
How hot does it get in Simms?
July, with a typical high of 83° and a low of 51°. About 8 days a year reach 90° (Fairfield, MT).
When is the first and last frost in Simms?
In half of years the last spring frost (32°) comes by May 13 and the first fall frost by September 27, about 135 frost-free days, at Fairfield, MT.
What growing zone is Simms 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 Simms?
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 Simms getting warmer?
Yes: 1991–2020 averaged 1.3° warmer than 1901–2000 on NOAA’s grid. A smaller shift than 57% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Simms.
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.