Dillon, 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 Dillon's primary NOAA station, DILLON 18 WSW - 2 stations mapped to the area.
The climate verdict for Dillon
Dryness leads the climate profile for Dillon, Montana, with 10.1 inches of precipitation a year. NOAA records an annual average of 39°F. July is the warmest month at 62°F and December the coldest at 18°F.
- 39°F
- average temperature, NOAA 1991-2020 normal
- 10.1"
- annual precipitation
Dillon: NOAA 1991-2020 normals describe a typical year, not a forecast. Method: /methodology.
Normals record plate
Sheet USW00004137 · Dillon, MT 39°F mean · 10.1" precip
TEMP-COLD · RANK-COOL · PHOTO-FINISH · PRCP-ARID · SWING-MID · COMF-UNK · LOAD-HEAT · STN-MULTI · BOOK-FULL
- TEMP-COLD 39°F
- RANK-COOL #274
- PHOTO-FINISH ≈ Sunshine
- PRCP-ARID 10.1"
- SWING-MID 45°F
- COMF-UNK Comfort n/a
- LOAD-HEAT 9,590 HDD
- STN-MULTI USW00004137
- BOOK-FULL 5/6 fields
Nearest mean-temperature peer: Sunshine, WY (+ 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.
- Dillon (this station) 39°F
- Hot E Glacier, MT 39°F
- Near Sunshine, WY 39°F
- Near Lennep, MT 39°F
- Near Scofield-skylin…, UT 39°F
Dillon 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 · Dillon
Dillon: 4/100 · grade F
Dillon publishes 3 of 6 Living Index dimensions (NOAA annual/seasonal normals · NOAA daily multivariate normals); 3 missing weights rescale to 100.
PlainClimate-derived for Dillon, not an official NOAA rating. Breakpoints and limits.
| Dimension | Station value | Score |
|---|---|---|
| Precipitation balance | 10.1 in · 24.9 from 35 in | 12/100 · F |
| Normal heat + freeze calendar | 229 calendar days | 2/100 · F |
| Annual temperature balance | 38.7°F · 28.8° from 67.5°F | 1/100 · F |
Dillon · 2026-08-04 · NOAA NCEI Climate Normals · method .
Dillon is a continental Köppen climate: Dfb
Coldest-month mean 17.5°F and warmest-month mean 62.4°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
- 62.4°F
- Coldest month
- 17.5°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 Dillon sits across the climate record
Three NOAA fields for Dillon's primary station, temperature, precipitation, and seasonal swing, are ranked against every station-mapped normal that carries the same field.
- Annual temperature
- Cooler than 96%
- Among 6,861 stations, Dillon sits in the cooler third of annual means.
- Annual precipitation
- Drier than 93%
- Dillon's annual total ranks in the drier third of 6,352 measured normals.
- Seasonal temperature swing
- 58th percentile swing
- Typical seasonal amplitude versus 6,861 complete station-years.
Monthly Temperatures
Average daily high and low temperatures by month
| Month | Avg High | Avg Low | Mean | Precip | Freeze Days | 90°F+ Days |
|---|---|---|---|---|---|---|
| January | 28°F (-2°C) | 8°F (-13°C) | 18°F (-8°C) | 0.3" | 30.9 | 0.0 |
| February | 32°F (0°C) | 9°F (-13°C) | 20°F (-6°C) | 0.6" | 27.5 | 0.0 |
| March | 41°F (5°C) | 18°F (-8°C) | 29°F (-1°C) | 0.6" | 29.8 | 0.0 |
| April | 50°F (10°C) | 26°F (-4°C) | 38°F (3°C) | 1.0" | 26.5 | 0.0 |
| May | 60°F (16°C) | 33°F (1°C) | 47°F (8°C) | 1.6" | 14.5 | 0.0 |
| June | 69°F (21°C) | 39°F (4°C) | 54°F (12°C) | 1.8" | 3.5 | 0.3 |
| July | 81°F (27°C) | 44°F (7°C) | 62°F (17°C) | 0.6" | 0.2 | 2.0 |
| August | 79°F (26°C) | 42°F (6°C) | 61°F (16°C) | 0.7" | 0.8 | 1.5 |
| September | 69°F (20°C) | 35°F (2°C) | 52°F (11°C) | 0.8" | 11.2 | 0.2 |
| October | 53°F (12°C) | 25°F (-4°C) | 39°F (4°C) | 0.9" | 25.1 | 0.0 |
| November | 39°F (4°C) | 15°F (-10°C) | 27°F (-3°C) | 0.5" | 28.6 | 0.0 |
| December | 28°F (-2°C) | 7°F (-14°C) | 18°F (-8°C) | 0.7" | 30.9 | 0.0 |
The year, day by day
Summer here tops out rather than builds: the warmest normal high is 83°F around July 23, short of 90°F on every date, while 229 dates carry a normal low at or below freezing, the coldest 6°F near December 19.
The freezing stretch
The normal low stays at or below 32°F into May 11, then returns to freezing around September 26, covering 229 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 26, when 40% of years recorded at least a hundredth of an inch. The driest is August 16 at 18%. Summed across the calendar, that is about 103 wet dates a year.
The widest day
July 21 carries the biggest normal gap between afternoon and dawn, 38°F between the normal high and the normal low.
Look up any date
Any date's 1991–2020 normal for Dillon.
Where Dillon Stands Nationally
Winters bite deep and often: the normal nightly low dips to freezing or below on around 229 nights a year, placing this among the most frost-prone tenth of ranked stations.
Aridity defines the water calendar: about 10 inches in a normal year lands this among the driest tenth of ranked stations.
Dillon earns 2 nationally notable standings (outer quintiles) against 6,860 NOAA 1991–2020 normals stations; only those extremes render.
Monthly Precipitation
Average monthly rainfall
7.8 days with precipitation
9.7 days with precipitation
9.3 days with precipitation
9.9 days with precipitation
11.5 days with precipitation
10.4 days with precipitation
5.9 days with precipitation
6.1 days with precipitation
6.2 days with precipitation
7.4 days with precipitation
7.7 days with precipitation
10.3 days with precipitation
Dillon spreads its precipitation across the year
Neither half of the year dominates here: June through August take 31% of the annual total and December through February 16%, with neither reaching the 35% that would mark a distinct wet season. Dillon has no dry season to plan around, though it does carry a 44.9°F seasonal spread.
The gap between the wettest and driest month still matters: June averages 1.8" and January 0.3". The three wettest months together take 44% 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.
Dillon is dry, and what does fall arrives gently
Only about 102 days a year record measurable precipitation here, 28% of the calendar, and they carry 10.1" between them. At roughly 0.10 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 May at about 12 wet days; the driest is July 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.
Frost Dates & Growing Season
First Fall Freeze
N/A
50% probability date
Last Spring Freeze
N/A
50% probability date
Heating & Cooling Degree Days
Annual totals indicate energy demand for heating and cooling
Heating Degree Days
9,590
Higher = more heating needed
Cooling Degree Days
35
Higher = more cooling needed
Warmest Month
July
Coldest Month
December
Nationwide similar cities
Other rankable U.S. places outside MT closest to Dillon 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 (39°F here).
- Leeds, ND 39°F · 0.0°F off
- Stanley, ND 39°F · 0.0°F off
- Fosston, MN 39°F · 0.1°F off
- Rugby, ND 39°F · 0.1°F off
Closest by annual precipitation
Nearest out-of-state peers by annual precipitation (10.1" here), excluding temperature-peer places.
- Koosharem, UT 10.1" · 0.0" off
- Shell, WY 10.1" · 0.0" off
- Santa Teresa, NM 10.1" · 0.0" off
- Homedale, ID 10.1" · 0.0" off
Scarce-water calendar
Where Dillon's limited precipitation lands
heating led · dry · mid swing
Dillon's energy balance leans toward cold weather: 9,590 annual heating degree days against 35 for cooling. Its 44.9°F seasonal range still makes the monthly rows more useful than the annual average alone.
A frost-free growing-season length is not available for Dillon. That missing field is kept separate from the observed temperature and precipitation record rather than filled from a regional estimate.
July and December mark the typical warm and cold ends of the calendar in Dillon's middle-range seasonal profile. The measured spread is 44.9°F. The annual average is 39°F. Neither the annual mean nor one extreme month represents the full calendar on its own.
Dillon's cold-season load does not imply a wet climate. Annual precipitation is 10.1 inches, which places the station in PlainClimate's dry range. Snowfall is not added to the interpretation because its annual value is missing. The snowfall and rainfall fields should be read separately rather than inferred from temperature.
Dillon wettest normal
June
June concentrates the scarce annual total (10.1 inches).
Dillon driest normal
January
January is typically driest; arid stations are defined by when water is absent, not by a four-season grid.
Questions about Dillon's climate
How dry is Dillon? ▼
How cold does Dillon get in winter? ▼
How much energy does heating and cooling require in Dillon? ▼
Data Sources
Data source: NOAA U.S. Climate Normals v1.0.1 (1991-2020). All figures on this page are from Dillon's primary station: DILLON 18 WSW (USW00004137). 2 NOAA stations are mapped to the Dillon area; the primary station's record is used for consistency. 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 3020800). Match rule for Dillon: 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 Dillon 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.