Photo: Tracey Elizabeth · CC BY 2.0Helena is among the driest of U.S. towns: 12 inches of precipitation a year
Midsummer highs settle at about 85°. By January nights alone, it runs colder than 86% of U.S. towns. Since 1901–2000, the year has warmed by 1.3°, most of all in January. Warm coats and heating bills mark the months from October to April, when means dip under 50°.
A year in Helena at a glance
Each month’s typical high and low, and what it brings.
What stands out about Helena’s climate
Compared with towns across the U.S., with Helena’s place in Montana beside it.
What a year in Helena 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 9 and the first by September 30. Frost and day counts come from NOAA’s station at Helena Rgnl Airport, 2.7 miles from the town’s center, 180 ft lower.
The 2023 USDA map puts Helena’s center in zone 5a: the coldest night of a typical winter, averaged over 1991–2020, reaches about −20°. 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 37 inches of snow a winter
Snow, measured at Helena Rgnl Airport, falls mostly in December. Precipitation (rain plus melted snow) adds up to 12 inches a year; June is the wettest month and January the driest. Rain or snow falls on about 91 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Helena
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 Helena Rgnl Airport.
Living with Helena’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 9 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 30.
Months with highs of 62–84° and lows of 40° or more: June, August and September. 75 miles of trails are waiting.
Parks & trails →Cold waves are 47% of the yearly building losses FEMA expects in Helena from natural hazards, the largest share. Normals are averages; the hazards page covers the extremes.
Natural hazards →Helena and its neighbors
Every town next door is within a degree of Helena in January and July, closer than the 5 km grid can tell apart. Tap a town to see its climate.
Climates most like Helena’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 |
|---|---|---|---|---|
| Helena, MT | 15° | 85° | 12" | 37" |
| Cody, WY | 14° | 85° | 11" | 45" |
| Taos, NM | 11° | 84° | 13" | 28" |
| Gypsum, CO | 11° | 86° | 14" | 39" |
| Doney Park, AZ | 17° | 86° | 16" | 52" |
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value. Snow and frost-free days come from the nearest weather station, so neighbors often share them.
Warmer than it used to be
The last 30 years in Helena averaged 1.3° warmer than the 1900s. The biggest change is in January (+4.2°).
A smaller shift than in 56% 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 Helena compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Helena’s place among Montana’s.
Helena weather by month
Highs, lows and precipitation from NOAA’s grid at Helena’s center; snow, wet days and snow on the ground from Helena Rgnl Airport. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 34° | 15° | 0.4" | 6.6" | 7 | 18 | 14° – 33° |
| February | 37° | 17° | 0.4" | 6.6" | 7 | 11 | 10° – 37° |
| March | 48° | 24° | 0.6" | 4.6" | 7 | 5 | 25° – 44° |
| April | 56° | 31° | 1.2" | 2.9" | 9 | 1 | 38° – 49° |
| May | 66° | 39° | 2.1" | 0.1" | 11 | 0 | 47° – 57° |
| June | 74° | 46° | 2.4" | 0.0" | 12 | 0 | 55° – 68° |
| July | 85° | 52° | 1.1" | 0.0" | 8 | 0 | 58° – 75° |
| August | 84° | 50° | 1.1" | 0.3" | 6 | 0 | 61° – 71° |
| September | 73° | 42° | 1.1" | 0.2" | 6 | 0 | 53° – 62° |
| October | 58° | 32° | 0.9" | 2.8" | 7 | 2 | 38° – 52° |
| November | 43° | 23° | 0.6" | 5.4" | 7 | 6 | 24° – 41° |
| December | 33° | 15° | 0.5" | 7.7" | 7 | 14 | 14° – 31° |
| Year | 58° | 32° | 12.4" | 37.2" | 91 | 57 |
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 37°. September is the most reliable, staying within 9°.
Where Helena’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 Helena’s center.
- Snow: Helena Rgnl Airport.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Helena Rgnl Airport, 2.7 miles from the town’s center, 180 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 Helena’s climate
What is the weather like in Helena?
A typical July afternoon reaches 85°, a January night drops to 15°, and about 37 inches of snow falls in a normal winter. Colder January nights than 86% of U.S. towns; cooler July afternoons than 52% of U.S. towns.
How cold does it get in Helena in winter?
January nights average 15°. About 170 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 14°.
How much snow does Helena get?
About 37 inches in a normal winter at Helena Rgnl Airport, most of it in December, with snow on the ground about 57 days a year.
How hot does it get in Helena?
July, with a typical high of 85° and a low of 52°. About 27 days a year reach 90° and 1 reach 100° (Helena Rgnl Airport).
When is the first and last frost in Helena?
In half of years the last spring frost (32°) comes by May 9 and the first fall frost by September 30, about 142 frost-free days, at Helena Rgnl Airport.
What growing zone is Helena in?
Zone 5a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −20°.
What is the best time of year to visit Helena?
By one simple rule (highs of 62–84° and lows of 40° or more), June, August and September. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Helena getting warmer?
Yes: 1991–2020 averaged 1.3° warmer than 1901–2000 on NOAA’s grid. A smaller shift than 56% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Helena.
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.