Dry weather: only 13 inches of rain and melted snow a year in Acton, less than in 94% of U.S. towns
High summer brings afternoon highs near 86°. Temperatures cover 71° across the year, low to high. Its January nights bite harder than in 83% of U.S. towns. Seedlings are safe outdoors from about May 10, with the first autumn frost due around October 1.
A year in Acton at a glance
Each month’s typical high and low, and what it brings.
What stands out about Acton’s climate
Compared with towns across the U.S., with Acton’s place in Montana beside it.
What a year in Acton feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 142 frost-free days a year
In half of years the last 32° night comes by May 10 and the first by October 1. Day counts come from NOAA’s station at Billings Logan International Airport, 11 miles from the town’s center, 250 ft lower; frost dates and degree days from Billings Wtp, MT, 14 miles away.
The 2023 USDA map puts Acton’s center in zone 5a: the coldest night of a typical winter, averaged over 1991–2020, reaches about −17°. 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 35 inches of snow a winter
Snow, measured at Billings Wtp, MT, falls mostly in December. Precipitation (rain plus melted snow) adds up to 13 inches a year; May is the wettest month and February the driest. Rain or snow falls on about 81 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Acton
93% 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 Billings Wtp, MT.
Living with Acton’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
142 frost-free days in zone 5a. 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: May, June and September.
Parks & trails →Cold waves are 32% of the yearly building losses FEMA expects in Acton from natural hazards, the largest share. Normals are averages; the hazards page covers the extremes.
Natural hazards →Acton and similar climates
TownRatings has no climate map of the towns around Acton yet.
Climates most like Acton’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 |
|---|---|---|---|---|
| Acton, MT | 16° | 86° | 13" | 35" |
| Glenwood Springs, CO | 14° | 87° | 15" | 39" |
| Edgewood, NM | 19° | 85° | 15" | 29" |
| Chubbuck, ID | 17° | 88° | 12" | 39" |
| Rapid City, SD | 14° | 86° | 19" | 36" |
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 Acton averaged 1.3° warmer than the 1900s. The biggest change is in January (+4.1°).
A smaller shift than in 53% 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 Acton compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Acton’s place among Montana’s.
Acton weather by month
Highs, lows and precipitation from NOAA’s grid at Acton’s center; snow, wet days and snow on the ground from Billings Wtp, MT. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 36° | 16° | 0.5" | 7.5" | 5 | 18 | 16° – 37° |
| February | 40° | 17° | 0.4" | 4.7" | 5 | 10 | 8° – 40° |
| March | 49° | 25° | 0.7" | 4.9" | 6 | 5 | 25° – 45° |
| April | 56° | 32° | 1.5" | 3.2" | 9 | 1 | 38° – 49° |
| May | 66° | 41° | 2.3" | 0.1" | 11 | 0 | 49° – 58° |
| June | 76° | 50° | 2.3" | 0.0" | 10 | 0 | 57° – 68° |
| July | 86° | 56° | 1.3" | 0.0" | 7 | 0 | 61° – 77° |
| August | 85° | 54° | 1.0" | 0.0" | 5 | 0 | 63° – 74° |
| September | 74° | 45° | 1.1" | 0.0" | 6 | 0 | 55° – 65° |
| October | 59° | 34° | 1.2" | 1.7" | 7 | 1 | 38° – 52° |
| November | 46° | 24° | 0.6" | 3.1" | 6 | 5 | 24° – 44° |
| December | 37° | 17° | 0.5" | 9.8" | 5 | 11 | 16° – 35° |
| Year | 59° | 34° | 13.4" | 35.0" | 81 | 52 |
How much a month can swing
A normal is an average. February swings the most: from 1991 to 2020 its average ranged from 8° to 40°. May is the most reliable, staying within 9°.
Where Acton’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 Acton’s center.
- Snow: Billings Wtp, MT.
- Frost dates, heating and cooling: Billings Wtp, MT, 14 miles away.
- Freezing nights, 90° and 100° days: Billings Logan International Airport, 11 miles from the town’s center, 250 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 Acton’s climate
What is the weather like in Acton?
A typical July afternoon reaches 86°, a January night drops to 16°, and about 35 inches of snow falls in a normal winter. Colder January nights than 83% of U.S. towns; hotter July afternoons than 55% of U.S. towns.
How cold does it get in Acton in winter?
January nights average 16°. About 142 nights a year reach 32° or below and 13 reach 0° or below. In the coldest January of the last 30 years the month averaged 16°.
How much snow does Acton get?
About 35 inches in a normal winter at Billings Wtp, MT, most of it in December, with snow on the ground about 52 days a year.
How hot does it get in Acton?
July, with a typical high of 86° and a low of 56°. About 32 days a year reach 90° and 2 reach 100° (Billings Wtp, MT).
When is the first and last frost in Acton?
In half of years the last spring frost (32°) comes by May 10 and the first fall frost by October 1, about 142 frost-free days, at Billings Wtp, MT.
What growing zone is Acton in?
Zone 5a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −17°.
What is the best time of year to visit Acton?
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 Acton getting warmer?
Yes: 1991–2020 averaged 1.3° warmer than 1901–2000 on NOAA’s grid. A smaller shift than 53% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Acton.
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.