Rimrock Colony sits near the bottom of U.S. towns for July heat
On a normal January night the air cools to about 11°. By precipitation alone, it ranks drier than 94% of U.S. towns. Since 1901–2000, the year has warmed by 1.8°, most of all in January. Warm coats and heating bills mark the months from October to May, when means dip under 50°.
A year in Rimrock Colony at a glance
Each month’s typical high and low, and what it brings.
What stands out about Rimrock Colony’s climate
Compared with towns across the U.S., with Rimrock Colony’s place in Montana beside it.
What a year in Rimrock Colony feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 132 frost-free days a year
In half of years the last 32° night comes by May 15 and the first by September 25. Frost and day counts come from NOAA’s station at Sweetgrass, MT, 9 miles from the town’s center, 460 ft lower.
The 2023 USDA map puts Rimrock Colony’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 14 inches of rain a year
June is the wettest month and December the driest.
Rain + melted snow by month
Inches of water
Heating and cooling a home in Rimrock Colony
96% of the work is heating, so the furnace matters far more than the air conditioner. Months averaging under 55° run from September 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 Sweetgrass, MT.
Living with Rimrock Colony’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
132 frost-free days in zone 4a. The last frost comes by May 15 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 25.
Months with highs of 62–84° and lows of 40° or more: June, July, August and September.
Parks & trails →Cold waves are 49% of the yearly building losses FEMA expects in Rimrock Colony from natural hazards, the largest share. Normals are averages; the hazards page covers the extremes.
Natural hazards →Rimrock Colony and similar climates
TownRatings has no climate map of the towns around Rimrock Colony 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 Rimrock Colony averaged 1.8° warmer than the 1900s. The biggest change is in January (+5.7°).
A bigger shift than in 77% 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 Rimrock Colony compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Rimrock Colony’s place among Montana’s.
Rimrock Colony weather by month
Highs, lows and precipitation from NOAA’s grid at Rimrock Colony’s center. 1991–2020 normals.
| Month | High | Low | Rain + melt | 30-yr range |
|---|---|---|---|---|
| January | 32° | 11° | 0.4" | 7° – 35° |
| February | 34° | 13° | 0.5" | −3° – 36° |
| March | 42° | 20° | 0.7" | 12° – 40° |
| April | 52° | 29° | 1.3" | 34° – 46° |
| May | 62° | 37° | 2.0" | 45° – 56° |
| June | 70° | 45° | 3.5" | 54° – 63° |
| July | 79° | 50° | 1.3" | 55° – 72° |
| August | 78° | 49° | 1.2" | 58° – 68° |
| September | 68° | 41° | 1.3" | 51° – 61° |
| October | 54° | 31° | 0.9" | 35° – 49° |
| November | 40° | 21° | 0.6" | 17° – 40° |
| December | 32° | 12° | 0.4" | 9° – 33° |
| Year | 54° | 30° | 14.0" |
How much a month can swing
A normal is an average. February swings the most: from 1991 to 2020 its average ranged from -3° to 36°. June is the most reliable, staying within 8°.
Where Rimrock Colony’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 Rimrock Colony’s center.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Sweetgrass, MT, 9 miles from the town’s center, 460 ft lower; 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 Rimrock Colony’s climate
What is the weather like in Rimrock Colony?
A typical July afternoon reaches 79°, a January night drops to 11°. Colder January nights than 92% of U.S. towns; cooler July afternoons than 95% of U.S. towns.
How cold does it get in Rimrock Colony in winter?
January nights average 11°. About 179 nights a year reach 32° or below and 28 reach 0° or below. In the coldest January of the last 30 years the month averaged 7°.
How hot does it get in Rimrock Colony?
July, with a typical high of 79° and a low of 50°. About 16 days a year reach 90° (Sweetgrass, MT).
When is the first and last frost in Rimrock Colony?
In half of years the last spring frost (32°) comes by May 15 and the first fall frost by September 25, about 132 frost-free days, at Sweetgrass, MT.
What growing zone is Rimrock Colony 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 Rimrock Colony?
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 Rimrock Colony getting warmer?
Yes: 1991–2020 averaged 1.8° warmer than 1901–2000 on NOAA’s grid. A bigger shift than 77% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Rimrock Colony.
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.