Hardly any U.S. towns collect less precipitation than Helena Valley Southeast: 12 inches a year
The coldest hours of a January night bottom out at 15° on average. Its January nights bite harder than in 85% of U.S. towns. Compared with 1901–2000, the average now sits 1.3° higher. Garden planting can start around May 9; autumn frost returns near September 30.
A year in Helena Valley Southeast at a glance
Each month’s typical high and low, and what it brings.
What stands out about Helena Valley Southeast’s climate
Compared with towns across the U.S., with Helena Valley Southeast’s place in Montana beside it.
What a year in Helena Valley Southeast 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, 3 miles from the town’s center, at about the same height.
The 2023 USDA map puts Helena Valley Southeast’s center in zone 4b: 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 Valley Southeast
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 Valley Southeast’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
142 frost-free days in zone 4b. 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. 9.5 miles of trails are waiting.
Parks & trails →Cold waves are 46% of the yearly building losses FEMA expects in Helena Valley Southeast from natural hazards, the largest share. Normals are averages; the hazards page covers the extremes.
Natural hazards →Helena Valley Southeast and its neighbors
Every town next door is within a degree of Helena Valley Southeast in January and July, closer than the 5 km grid can tell apart. Tap a town to see its climate.
Climates most like Helena Valley Southeast’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 Valley Southeast, 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 Valley Southeast averaged 1.3° warmer than the 1900s. The biggest change is in January (+4.2°).
A smaller shift than in 58% 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 Valley Southeast compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Helena Valley Southeast’s place among Montana’s.
Helena Valley Southeast weather by month
Highs, lows and precipitation from NOAA’s grid at Helena Valley Southeast’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° | 0.3" | 6.6" | 7 | 18 | 15° – 33° |
| February | 37° | 17° | 0.4" | 6.6" | 7 | 11 | 9° – 37° |
| March | 48° | 24° | 0.5" | 4.6" | 7 | 5 | 25° – 44° |
| April | 56° | 32° | 1.2" | 2.9" | 9 | 1 | 39° – 49° |
| May | 66° | 40° | 2.0" | 0.1" | 11 | 0 | 47° – 57° |
| June | 74° | 47° | 2.4" | 0.0" | 12 | 0 | 55° – 68° |
| July | 85° | 53° | 1.1" | 0.0" | 8 | 0 | 59° – 76° |
| August | 84° | 51° | 1.0" | 0.3" | 6 | 0 | 61° – 71° |
| September | 73° | 43° | 1.1" | 0.2" | 6 | 0 | 53° – 62° |
| October | 58° | 33° | 0.9" | 2.8" | 7 | 2 | 38° – 52° |
| November | 43° | 23° | 0.5" | 5.4" | 7 | 6 | 24° – 42° |
| December | 34° | 16° | 0.4" | 7.7" | 7 | 14 | 14° – 31° |
| Year | 58° | 33° | 11.8" | 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 9° to 37°. September is the most reliable, staying within 9°.
Where Helena Valley Southeast’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 Valley Southeast’s center.
- Snow: Helena Rgnl Airport.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Helena Rgnl Airport, 3 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 Helena Valley Southeast’s climate
What is the weather like in Helena Valley Southeast?
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 85% of U.S. towns; cooler July afternoons than 52% of U.S. towns.
How cold does it get in Helena Valley Southeast 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 15°.
How much snow does Helena Valley Southeast 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 Valley Southeast?
July, with a typical high of 85° and a low of 53°. About 27 days a year reach 90° and 1 reach 100° (Helena Rgnl Airport).
When is the first and last frost in Helena Valley Southeast?
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 Valley Southeast in?
Zone 4b 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 Valley Southeast?
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 Valley Southeast getting warmer?
Yes: 1991–2020 averaged 1.3° warmer than 1901–2000 on NOAA’s grid. A smaller shift than 58% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Helena Valley Southeast.
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.