Helena, MT Climate: Temperature & Rain by Month
Pulled from NOAA NCEI 1991–2020 normals →: climate measurements used in PlainClimate's documented score
30-year climate normals (1991-2020) from Helena's primary NOAA station, HELENA RGNL AP.
The climate verdict for Helena
Dryness leads the climate profile for Helena, Montana, with 11.4 inches of precipitation a year. NOAA records an annual average of 46°F. At 49/100 (moderate) the climate comfort score falls in the bottom third of the station-mapped U.S. score corpus, exceeding only 18% of scores.
- 46°F
- annual average temperature (NOAA normal)
- 49/100
- comfort score, above 18% of station-mapped location scores
- 11.4"
- annual precipitation · 37" snow
- 144 days
- frost-free days per growing season
Helena: NOAA 1991-2020 normals describe a typical year, not a forecast. Method: /methodology.
Normals record plate
Sheet USW00024144 · Helena, MT 46°F mean · 11.4" precip
TEMP-COOL · RANK-COOL · PHOTO-FINISH · PRCP-ARID · SWING-WIDE · COMF-LOW · LOAD-HEAT · STN-1 · BOOK-FULL
- TEMP-COOL 46°F
- RANK-COOL #1,441
- PHOTO-FINISH ≈ Enosburg Falls
- PRCP-ARID 11.4"
- SWING-WIDE 48°F
- COMF-LOW 49/100
- LOAD-HEAT 7,499 HDD
- STN-1 USW00024144
- BOOK-FULL 6/6 fields
Nearest mean-temperature peer: Enosburg Falls, VT (+ 0 °F mean)
Instrument codes from this station's NOAA 1991–2020 normals, mean temperature, corpus warmth rank, photo-finish peer station, precipitation band, seasonal swing, comfort composite, degree-day load, and field book, not a livability rating.
Mean-temperature neighbourhood
Nationwide NOAA normal poles and nearest peers, not a reprint of every MT station list.
- Helena (this station) 46°F
- Hot Casper Natrona…, WY 46°F
- Near Enosburg Falls, VT 46°F
- Cold N Conway, NH 45°F
- Near Deadwood, SD 45°F
Helena sits in Montana, the #6 coldest U.S. state at 43.4°F statewide annual average - see all 50 coldest states ranked by NOAA normals
Climate Living Index · Helena
Helena: 27/100 · grade F
Helena publishes all six Living Index dimensions from NOAA annual/seasonal normals · NOAA daily multivariate normals · NOAA hourly normals.
PlainClimate-derived for Helena, not an official NOAA rating. Rankings still use Comfort Score 49/100 (separate formula). Breakpoints and limits.
| Dimension | Station value | Score |
|---|---|---|
| Summer moisture balance | 42.8°F mean dew point | 48/100 · D |
| Snowfall burden | 37.2 inches/year | 31/100 · F |
| Normal heat + freeze calendar | 178 calendar days | 26/100 · F |
| Annual temperature balance | 45.5°F · 22.0° from 67.5°F | 21/100 · F |
| Frost-free season | 144 days/year | 21/100 · F |
| Precipitation balance | 11.4 in · 23.6 from 35 in | 17/100 · F |
Helena · 2026-08-04 · NOAA NCEI Climate Normals · method · Comfort Score method.
Helena's normals sit in a dry climate class: BSk
Precipitation is low relative to temperature but above true desert thresholds: cold semi-arid steppe (BSk). Class BSk is the Peel et al. (2007) label for this station's monthly mean temperature and precipitation normals: dry (arid or semi-arid), specifically cold semi-arid steppe.
- Köppen code
- BSk
- Group
- Dry (arid or semi-arid)
- Warmest month
- 70.6°F
- Coldest month
- 23.0°F
Source: official public datasets monthly normals (1991–2020) at the city’s primary station. This is a station classification, not a mapped regional consensus.
National standing · heating-led station
Where Helena sits across the climate record
Three NOAA fields for Helena's primary station, temperature, precipitation, and seasonal swing, are ranked against every station-mapped normal that carries the same field.
- Annual temperature
- Cooler than 79%
- Among 6,861 stations, Helena sits in the cooler third of annual means.
- Annual precipitation
- Drier than 91%
- Helena's annual total ranks in the drier third of 6,352 measured normals.
- Seasonal temperature swing
- Wider than 71%
- Warmest-to-coldest month gap for Helena is large versus 6,861 complete station-years.
How Helena compares across U.S. station-mapped locations
Helena's comfort score vs. all station-mapped locations
PlainClimate composite comfort index (1–100), NOAA 1991–2020 normals
49 18th percentile score exceeds 18% of 6,189 station-mapped location scores
- 0–10: 0 station-mapped locations (0%). Below this entry.
- 10–20: 0 station-mapped locations (0%). Below this entry.
- 20–30: 96 station-mapped locations (2%). Below this entry.
- 30–40: 280 station-mapped locations (5%). Below this entry.
- 40–50: 1,113 station-mapped locations (18%). This entry sits in this band.
- 50–60: 1,329 station-mapped locations (21%). Above this entry.
- 60–70: 1,236 station-mapped locations (20%). Above this entry.
- 70–80: 650 station-mapped locations (11%). Above this entry.
- 80–90: 921 station-mapped locations (15%). Above this entry.
- 90–100: 564 station-mapped locations (9%). Above this entry.
Source NOAA U.S. Climate Normals, PlainClimate comfort index · 1991–2020
Helena's measured station temperature trend
MethodologyAcross 127 complete annual observations from 1892 to 2025, HELENA RGNL AP warmed at a fitted rate of 0.14°C per decade. The line shows the fitted change relative to its first year, not raw year-to-year temperatures or a forecast.
- Helena primary station fitted change +0.14 °C/decade
Monthly Temperatures
Average daily high and low temperatures by month
| Month | Avg High | Avg Low | Mean | Precip | Snow | Freeze Days | 90°F+ Days |
|---|---|---|---|---|---|---|---|
| January | 32°F (0°C) | 14°F (-10°C) | 23°F (-5°C) | 0.4" | 6.6" | 29.4 | 0.0 |
| February | 37°F (3°C) | 17°F (-8°C) | 27°F (-3°C) | 0.4" | 6.6" | 26.0 | 0.0 |
| March | 48°F (9°C) | 25°F (-4°C) | 36°F (2°C) | 0.5" | 4.6" | 25.4 | 0.0 |
| April | 57°F (14°C) | 32°F (0°C) | 45°F (7°C) | 1.0" | 2.9" | 15.1 | 0.0 |
| May | 66°F (19°C) | 42°F (5°C) | 54°F (12°C) | 1.9" | 0.1" | 3.4 | 0.3 |
| June | 75°F (24°C) | 49°F (9°C) | 62°F (17°C) | 2.2" | 0.0" | 0.1 | 2.4 |
| July | 86°F (30°C) | 55°F (13°C) | 71°F (21°C) | 1.1" | 0.0" | 0.0 | 12.2 |
| August | 85°F (29°C) | 53°F (12°C) | 69°F (20°C) | 1.0" | 0.3" | 0.0 | 10.6 |
| September | 73°F (23°C) | 45°F (7°C) | 59°F (15°C) | 1.0" | 0.2" | 1.7 | 1.8 |
| October | 58°F (14°C) | 34°F (1°C) | 46°F (8°C) | 0.8" | 2.8" | 13.8 | 0.0 |
| November | 43°F (6°C) | 23°F (-5°C) | 33°F (0°C) | 0.6" | 5.4" | 25.3 | 0.0 |
| December | 33°F (0°C) | 14°F (-10°C) | 23°F (-5°C) | 0.5" | 7.7" | 29.7 | 0.0 |
The year, day by day
Summer here tops out rather than builds: the warmest normal high is 89°F around July 27, short of 90°F on every date, while 178 dates carry a normal low at or below freezing, the coldest 12°F near January 1.
The freezing stretch
The normal low stays at or below 32°F into April 14, then returns to freezing around October 20, covering 178 dates in all.
Derived from the normal daily minimum. This is a different measure from the 50%-probability frost dates shown elsewhere on this page, which come from NOAA’s frost product.
Where the wet dates fall
The likeliest wet date is May 31, when 41% of years recorded at least a hundredth of an inch. The driest is September 18 at 20%. Summed across the calendar, that is about 91 wet dates a year.
The widest day
July 29 carries the biggest normal gap between afternoon and dawn, 32°F between the normal high and the normal low.
Look up any date
Any date's 1991–2020 normal for Helena.
Where Helena Stands Nationally
Aridity defines the water calendar: about 11 inches in a normal year lands this among the driest tenth of ranked stations.
Helena earns one nationally notable standing (outer quintile) against 6,860 NOAA 1991–2020 normals stations, middle-of-the-pack metrics stay silent here.
Monthly Precipitation
Average monthly rainfall and snowfall
Snow: 6.6"
6.5 days with precipitation
Snow: 6.6"
6.5 days with precipitation
Snow: 4.6"
6.9 days with precipitation
Snow: 2.9"
8.8 days with precipitation
Snow: 0.1"
11.2 days with precipitation
11.5 days with precipitation
7.5 days with precipitation
Snow: 0.3"
6.3 days with precipitation
Snow: 0.2"
5.8 days with precipitation
Snow: 2.8"
7.0 days with precipitation
Snow: 5.4"
6.5 days with precipitation
Snow: 7.7"
6.6 days with precipitation
Helena runs a summer-peaked wet season
38% of Helena's yearly precipitation falls in June, July and August alone, against the 25% an evenly spread year would give those three months. The wettest month is June at 2.2", on a wide 47.6°F gap between its warmest and coldest month. Warm-season convection and, across the Southwest, the North American monsoon produce this shape: rain arrives in short heavy bursts during the hottest part of the year rather than as long cool-season soaking.
- Wettest three months: June, May, July, taking 46% of the annual total between them.
- Driest month: January at 0.4".
- Winter share: 11% falls in December, January and February.
Shares are computed from this station's own 1991-2020 monthly precipitation normals. A summer-peaked label means the June-August share reaches 35%; it describes timing across an average year, not any single season, and says nothing about how heavy an individual storm can be.
Helena is dry, and what does fall arrives gently
Only about 91 days a year record measurable precipitation here, 25% of the calendar, and they carry 11.4" between them. At roughly 0.13 inches on an average wet day, this is not the damp drizzle of a marine climate; it is an arid record in which precipitation is both uncommon and light when it appears.
The wettest month by count is June at about 12 wet days; the driest is September at about 6.
A low per-event average in a dry record is a statement about typical days only. Arid regions can still take a large share of a year's total from a single convective storm, which a normal cannot show.
A wet day is one recording at least 0.01 inches. These are 1991-2020 normals: they describe an average year, not the extremes within it.
Winter brings real snow to Helena
Helena averages 37.2 inches of snowfall a year, with December the snowiest month on the normals, spread across roughly 28 days that record measurable snow. That is depth accumulating on the ground, which is why it can exceed the annual precipitation figure: precipitation counts the liquid the snow melts down to, and fresh snow is mostly air.
- Annual snowfall: 37.2 inches of depth.
- Days recording measurable snow: about 28 a year.
- At a rough ten-to-one melt ratio, snow accounts for on the order of 33% of the year's precipitation.
NOAA 1991-2020 normals. The ten-to-one ratio is a convention, not a measurement: real ratios vary with temperature, so treat the share as an order of magnitude rather than an exact split.
Frost Dates & Growing Season
First Fall Freeze
September 30
50% probability date
Last Spring Freeze
May 9
50% probability date
Growing Season
144 days
Heating & Cooling Degree Days
Annual totals indicate energy demand for heating and cooling
Heating Degree Days
7,499
Higher = more heating needed
Cooling Degree Days
434
Higher = more cooling needed
Warmest Month
July
Coldest Month
January
Humidity & Wind
Monthly averages from hourly observations
| Month | Humidity | Wind (mph) | Clear Sky % | Overcast % |
|---|---|---|---|---|
| January | 67% | 5.9 | 43% | 29% |
| February | 61% | 6.5 | 41% | 30% |
| March | 54% | 7.9 | 39% | 29% |
| April | 49% | 8.8 | 46% | 25% |
| May | 54% | 7.7 | 44% | 26% |
| June | 46% | 7.5 | 66% | 10% |
| July | 40% | 6.7 | 75% | 6% |
| August | 43% | 6.4 | 69% | 10% |
| September | 51% | 6.2 | 64% | 17% |
| October | 60% | 6.2 | 51% | 26% |
| November | 66% | 5.8 | 45% | 30% |
| December | 69% | 5.1 | 40% | 33% |
Nationwide similar cities
Other rankable U.S. places outside MT closest to Helena on two NOAA annual-normal axes (mean temperature and annual precipitation). Chip rows use distinct link sets.
Closest by average temperature
Nearest out-of-state peers by annual mean temperature (46°F here).
- Big Horn, WY 46°F · 0.0°F off
- Britt, IA 46°F · 0.0°F off
- Caledonia, MN 46°F · 0.0°F off
- Charlevoix, MI 46°F · 0.0°F off
Closest by annual precipitation
Nearest out-of-state peers by annual precipitation (11.4" here), excluding temperature-peer places.
- Jackpot, NV 11.4" · 0.0" off
- Quemado, NM 11.4" · 0.0" off
- Springerville, AZ 11.4" · 0.0" off
- Window Rock, AZ 11.3" · 0.1" off
Snow and freeze rhythm
When cold and snow define Helena
heating led · dry · mid swing
Helena's energy balance leans toward cold weather: 7,499 annual heating degree days against 434 for cooling. Its 47.6°F seasonal range still makes the monthly rows more useful than the annual average alone.
Only about 144 days are frost-free in a normal year. That short interval is consistent with the cold-season signal, but the measure does not predict the exact first or last freeze in any one year.
-
1. Helena coldest normal
January
Averaging 23°F (-5°C), this month sits below freezing for the month as a whole, not merely overnight.
-
2. Helena typical freeze period
January through December
The station reports average freezing days from January through December.
-
3. Helena snow peak
December
Helena averages 37.2 inches of snow a year, with December the snowiest month on the normals.
Questions about Helena's climate
How much snow does Helena get? ▼
How cold does Helena get in winter? ▼
How much energy does heating and cooling require in Helena? ▼
Data Sources
Data source: NOAA U.S. Climate Normals v1.0.1 (1991-2020). All figures on this page are from Helena's primary station: HELENA RGNL AP (USW00024144). For informational purposes only.
Place identity: U.S. Census Bureau 2024 Gazetteer places. The 2024 Census Gazetteer identifies the exact name-and-state match as an incorporated place (GEOID 3035600). Match rule for Helena: exact normalized name + state only, no fuzzy expansion, so nearby differently spelled facilities stay unmatched.
On this page every temperature, precipitation, and derived score for Helena comes from its primary NOAA station record. No figure on this page is typed in by an editor - each value is rendered from NOAA 1991-2020 U.S. Climate Normals. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of 1991–2020 normals.