Hebgen Dam, MT Climate: Temperature & Rain by Month
Temperature and precipitation from NOAA NCEI 1991–2020 normals →, plus PlainClimate's derived comfort score
30-year climate normals (1991-2020) from Hebgen Dam's primary NOAA station, HEBGEN DAM.
The climate verdict for Hebgen Dam
Hebgen Dam, Montana has a mixed annual climate rather than one dominant extreme. Its NOAA normal shows an annual average of 37°F. At 44/100 (moderate) the climate comfort score falls in the bottom third of the station-mapped U.S. score corpus, exceeding only 10% of scores.
- 37°F
- annual average temperature (NOAA normal)
- 44/100
- comfort score, above 10% of station-mapped location scores
- 28.6"
- annual precipitation · 177" snow
- 87 days
- growing season, frost-free days
Hebgen Dam: NOAA 1991-2020 normals describe a typical year, not a forecast. Method: /methodology.
Normals record plate
Sheet USC00244038 · Hebgen Dam, MT 37°F mean · 28.6" precip
TEMP-COLD · RANK-COOL · PHOTO-FINISH · PRCP-MID · SWING-WIDE · COMF-LOW · LOAD-HEAT · STN-1 · BOOK-FULL
- TEMP-COLD 37°F
- RANK-COOL #137
- PHOTO-FINISH ≈ Rio Grande Rsvr
- PRCP-MID 28.6"
- SWING-WIDE 49°F
- COMF-LOW 44/100
- LOAD-HEAT 10,200 HDD
- STN-1 USC00244038
- BOOK-FULL 6/6 fields
Nearest mean-temperature peer: Rio Grande Rsvr, CO ( -0.1 °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.
- Hebgen Dam (this station) 37°F
- Cold Rio Grande Rsvr, CO 37°F
- Near Sargents, CO 37°F
- Near Tower Falls, WY 37°F
- Near Grand Lake, CO 37°F
Hebgen Dam 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 · Hebgen Dam
Hebgen Dam: 15/100 · grade F
Hebgen Dam publishes 5 of 6 Living Index dimensions (NOAA annual/seasonal normals · NOAA daily multivariate normals); 1 missing weight rescale to 100.
PlainClimate-derived for Hebgen Dam, not an official NOAA rating. Rankings still use Comfort Score 44/100 (separate formula). Breakpoints and limits.
| Dimension | Station value | Score |
|---|---|---|
| Precipitation balance | 28.6 in · 6.4 from 35 in | 77/100 · B |
| Normal heat + freeze calendar | 223 calendar days | 4/100 · F |
| Annual temperature balance | 37.0°F · 30.5° from 67.5°F | 0/100 · F |
| Frost-free season | 87 days/year | 0/100 · F |
| Snowfall burden | 177.2 inches/year | 0/100 · F |
Hebgen Dam · 2026-08-04 · NOAA NCEI Climate Normals · method · Comfort Score method.
Hebgen Dam is a continental Köppen climate: Dfb
Coldest-month mean 13.2°F and warmest-month mean 61.7°F place this station in continental, no dry season, warm summer climates (Dfb). Class Dfb is the Peel et al. (2007) label for this station's monthly mean temperature and precipitation normals: continental, specifically continental, no dry season, warm summer.
- Köppen code
- Dfb
- Group
- Continental
- Warmest month
- 61.7°F
- Coldest month
- 13.2°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 Hebgen Dam sits across the climate record
Three NOAA fields for Hebgen Dam's primary station, temperature, precipitation, and seasonal swing, are ranked against every station-mapped normal that carries the same field.
- Annual temperature
- Cooler than 98%
- Among 6,861 stations, Hebgen Dam sits in the cooler third of annual means.
- Annual precipitation
- 38th percentile wetness
- Neither arid nor torrential versus 6,352 station totals.
- Seasonal temperature swing
- Wider than 75%
- Warmest-to-coldest month gap for Hebgen Dam is large versus 6,861 complete station-years.
How Hebgen Dam compares across U.S. station-mapped locations
Hebgen Dam's comfort score vs. all station-mapped locations
PlainClimate composite comfort index (1–100), NOAA 1991–2020 normals
44 10th percentile score exceeds 10% 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
Hebgen Dam's measured station temperature trend
MethodologyAcross 75 complete annual observations from 1914 to 2025, HEBGEN DAM warmed at a fitted rate of 0.04°C per decade. The line shows the fitted change relative to its first year, not raw year-to-year temperatures or a forecast.
- Hebgen Dam primary station fitted change +0.04 °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 | 23°F (-5°C) | 4°F (-16°C) | 13°F (-10°C) | 3.1" | 43.8" | 31.0 | 0.0 |
| February | 28°F (-2°C) | 5°F (-15°C) | 17°F (-9°C) | 2.8" | 33.7" | 28.0 | 0.0 |
| March | 38°F (4°C) | 14°F (-10°C) | 26°F (-3°C) | 2.2" | 20.6" | 30.4 | 0.0 |
| April | 47°F (8°C) | 23°F (-5°C) | 35°F (2°C) | 2.3" | 7.7" | 27.6 | 0.0 |
| May | 58°F (15°C) | 32°F (0°C) | 45°F (7°C) | 3.1" | 1.2" | 15.7 | 0.0 |
| June | 68°F (20°C) | 39°F (4°C) | 54°F (12°C) | 3.0" | 0.0" | 3.3 | 0.1 |
| July | 79°F (26°C) | 45°F (7°C) | 62°F (17°C) | 1.6" | 0.0" | 0.3 | 1.1 |
| August | 78°F (26°C) | 43°F (6°C) | 61°F (16°C) | 1.4" | 0.0" | 0.5 | 0.4 |
| September | 68°F (20°C) | 37°F (3°C) | 52°F (11°C) | 1.6" | 0.0" | 6.8 | 0.1 |
| October | 51°F (10°C) | 28°F (-2°C) | 39°F (4°C) | 2.1" | 4.1" | 22.5 | 0.0 |
| November | 34°F (1°C) | 18°F (-8°C) | 26°F (-3°C) | 2.5" | 20.9" | 28.8 | 0.0 |
| December | 23°F (-5°C) | 6°F (-15°C) | 14°F (-10°C) | 3.1" | 45.2" | 30.9 | 0.0 |
The year, day by day
Summer here tops out rather than builds: the warmest normal high is 81°F around July 26, short of 90°F on every date, while 223 dates carry a normal low at or below freezing, the coldest 3°F near January 1.
The freezing stretch
The normal low stays at or below 32°F into May 14, then returns to freezing around October 5, covering 223 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 January 5, when 45% of years recorded at least a hundredth of an inch. The driest is September 2 at 20%. Summed across the calendar, that is about 119 wet dates a year.
The widest day
July 29 carries the biggest normal gap between afternoon and dawn, 35°F between the normal high and the normal low.
Look up any date
Any date's 1991–2020 normal for Hebgen Dam.
Where Hebgen Dam Stands Nationally
Winters bite deep and often: the normal nightly low dips to freezing or below on around 223 nights a year, placing this among the most frost-prone tenth of ranked stations.
Daily temperature swings run wider than most of the country, peaking near 35°F between the normal high and low.
Hebgen Dam earns 2 nationally notable standings (outer quintiles) against 6,860 NOAA 1991–2020 normals stations; only those extremes render.
Monthly Precipitation
Average monthly rainfall and snowfall
Snow: 43.8"
13.7 days with precipitation
Snow: 33.7"
10.5 days with precipitation
Snow: 20.6"
9.2 days with precipitation
Snow: 7.7"
9.8 days with precipitation
Snow: 1.2"
11.5 days with precipitation
11.7 days with precipitation
7.8 days with precipitation
6.4 days with precipitation
5.5 days with precipitation
Snow: 4.1"
8.3 days with precipitation
Snow: 20.9"
10.2 days with precipitation
Snow: 45.2"
13.0 days with precipitation
Hebgen Dam spreads its precipitation across the year
Neither half of the year dominates here: June through August take 21% of the annual total and December through February 31%, with neither reaching the 35% that would mark a distinct wet season. Hebgen Dam has no dry season to plan around, though it does carry a wide 48.5°F gap between its warmest and coldest month.
The gap between the wettest and driest month still matters: May averages 3.1" and August 1.4". The three wettest months together take 32% of the year, against the 25% a perfectly flat distribution would give them.
Shares are computed from this station's own 1991-2020 monthly precipitation normals. "Spread across the year" means neither the June-August nor the December-February share reaches 35%; it describes an average year, not the variability of any single one.
How Hebgen Dam's precipitation splits across the calendar
About 118 days a year record measurable precipitation here, carrying 28.6" between them, or roughly 0.24 inches on a typical wet day. That sits in the middle band: neither the many-light-days pattern of the Pacific Northwest and the Great Lakes, nor the few-heavy-events pattern of the Gulf and the desert Southwest.
A wet day is one recording at least 0.01 inches. These are 1991-2020 normals: they describe an average year and say nothing about the heaviest single storm on record.
Winter brings real snow to Hebgen Dam
Hebgen Dam averages 177.2 inches of snowfall a year, with December the snowiest month on the normals, spread across roughly 51 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: 177.2 inches of depth.
- Days recording measurable snow: about 51 a year.
- At a rough ten-to-one melt ratio, snow accounts for on the order of 62% 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 10
50% probability date
Last Spring Freeze
June 15
50% probability date
Growing Season
87 days
Heating & Cooling Degree Days
Annual totals indicate energy demand for heating and cooling
Heating Degree Days
10,200
Higher = more heating needed
Cooling Degree Days
32
Higher = more cooling needed
Warmest Month
July
Coldest Month
January
Nationwide similar cities
Other rankable U.S. places outside MT closest to Hebgen Dam 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 (37°F here).
- Grand Lake, CO 37°F · 0.1°F off
- Palmer, AK 37°F · 0.1°F off
- Tower, MN 37°F · 0.1°F off
- Island Park, ID 37°F · 0.2°F off
Closest by annual precipitation
Nearest out-of-state peers by annual precipitation (28.6" here), excluding temperature-peer places.
- Granite Falls, MN 28.6" · 0.0" off
- Yankton, SD 28.7" · 0.0" off
- Alton, KS 28.6" · 0.0" off
- Pipestone, MN 28.6" · 0.0" off
Snow and freeze rhythm
When cold and snow define Hebgen Dam
heating led · moderate · mid swing
Hebgen Dam's energy balance leans toward cold weather: 10,200 annual heating degree days against 32 for cooling. Its 48.5°F seasonal range still makes the monthly rows more useful than the annual average alone.
Only about 87 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. Hebgen Dam coldest normal
January
Averaging 13°F (-10°C), this month sits below freezing for the month as a whole, not merely overnight.
-
2. Hebgen Dam typical freeze period
January through December
The station reports average freezing days from January through December.
-
3. Hebgen Dam snow peak
December
Hebgen Dam averages 177.2 inches of snow a year, with December the snowiest month on the normals.
Questions about Hebgen Dam's climate
How much snow does Hebgen Dam get? ▼
How cold does Hebgen Dam get in winter? ▼
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Data Sources
Data source: NOAA U.S. Climate Normals v1.0.1 (1991-2020). All figures on this page are from Hebgen Dam's primary station: HEBGEN DAM (USC00244038). For informational purposes only.
Place identity: U.S. Census Bureau 2024 Gazetteer places. The conservative exact name-and-state crosswalk finds no Census place match, so PlainClimate treats this as a station-mapped location and does not claim it is a municipality. No exact Gazetteer row for Hebgen Dam; facility counts that depend on place identity are therefore an upper bound, not a municipal census.
On this page every temperature, precipitation, and derived score for Hebgen Dam 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.