Roundup, MT Climate: Temperature & Rain by Month
Average temperature and precipitation from NOAA NCEI 1991–2020 normals →, with a derived climate comfort score
30-year climate normals (1991-2020) from Roundup's primary NOAA station, ROUNDUP - 2 stations mapped to the area.
The climate verdict for Roundup
Dryness leads the climate profile for Roundup, Montana, with 14.9 inches of precipitation a year. NOAA records an annual average of 47°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.
- 47°F
- yearly average temperature, NOAA normal
- 49/100
- comfort score, above 18% of station-mapped location scores
- 14.9"
- annual precipitation · 24" snow
- 124 days
- frost-free days per growing season
Roundup: NOAA 1991-2020 normals describe a typical year, not a forecast. Method: /methodology.
Normals record plate
Sheet USC00247214 · Roundup, MT 47°F mean · 14.9" precip
TEMP-COOL · RANK-COOL · PHOTO-FINISH · PRCP-DRY · SWING-WIDE · COMF-LOW · LOAD-HEAT · STN-MULTI · BOOK-FULL
- TEMP-COOL 47°F
- RANK-COOL #1,715
- PHOTO-FINISH ≈ Meredith
- PRCP-DRY 14.9"
- SWING-WIDE 46°F
- COMF-LOW 49/100
- LOAD-HEAT 7,193 HDD
- STN-MULTI USC00247214
- BOOK-FULL 6/6 fields
Nearest mean-temperature peer: Meredith, NH (+ 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.
- Roundup (this station) 47°F
- Hot Woodland, ME 47°F
- Near Meredith, NH 47°F
- Near NW Michigan Rsc…, MI 47°F
- Cold Sandusky, MI 46°F
Roundup 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 · Roundup
Roundup: 21/100 · grade F
Roundup publishes 5 of 6 Living Index dimensions (NOAA annual/seasonal normals · NOAA daily multivariate normals); 1 missing weight rescale to 100.
PlainClimate-derived for Roundup, not an official NOAA rating. Rankings still use Comfort Score 49/100 (separate formula). Breakpoints and limits.
| Dimension | Station value | Score |
|---|---|---|
| Snowfall burden | 24.4 inches/year | 44/100 · D |
| Precipitation balance | 14.9 in · 20.1 from 35 in | 28/100 · F |
| Annual temperature balance | 46.5°F · 21.0° from 67.5°F | 25/100 · F |
| Frost-free season | 124 days/year | 9/100 · F |
| Normal heat + freeze calendar | 216 calendar days | 7/100 · F |
Roundup · 2026-08-04 · NOAA NCEI Climate Normals · method · Comfort Score method.
Roundup'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
- 71.2°F
- Coldest month
- 25.1°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 Roundup sits across the climate record
Three NOAA fields for Roundup's primary station, temperature, precipitation, and seasonal swing, are ranked against every station-mapped normal that carries the same field.
- Annual temperature
- Cooler than 75%
- Among 6,861 stations, Roundup sits in the cooler third of annual means.
- Annual precipitation
- Drier than 83%
- Roundup's annual total ranks in the drier third of 6,352 measured normals.
- Seasonal temperature swing
- 64th percentile swing
- Typical seasonal amplitude versus 6,861 complete station-years.
How Roundup compares across U.S. station-mapped locations
Roundup'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
Roundup's measured station temperature trend
MethodologyAcross 49 complete annual observations from 1919 to 2017, ROUNDUP warmed at a fitted rate of 0.12°C per decade. The line shows the fitted change relative to its first year, not raw year-to-year temperatures or a forecast.
- Roundup primary station fitted change +0.11 °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 | 37°F (3°C) | 13°F (-10°C) | 25°F (-4°C) | 0.4" | 5.2" | 27.4 | 0.0 |
| February | 41°F (5°C) | 15°F (-9°C) | 28°F (-2°C) | 0.4" | 3.9" | 25.2 | 0.0 |
| March | 51°F (10°C) | 22°F (-5°C) | 36°F (2°C) | 0.7" | 4.4" | 24.5 | 0.0 |
| April | 60°F (16°C) | 30°F (-1°C) | 45°F (7°C) | 1.7" | 1.4" | 15.4 | 0.0 |
| May | 69°F (21°C) | 39°F (4°C) | 54°F (12°C) | 2.5" | 0.1" | 3.9 | 0.8 |
| June | 78°F (26°C) | 48°F (9°C) | 63°F (17°C) | 2.9" | 0.0" | 0.1 | 4.4 |
| July | 89°F (32°C) | 54°F (12°C) | 71°F (22°C) | 1.7" | 0.0" | 0.0 | 17.6 |
| August | 88°F (31°C) | 51°F (11°C) | 70°F (21°C) | 1.2" | 0.0" | 0.1 | 15.7 |
| September | 77°F (25°C) | 42°F (6°C) | 60°F (15°C) | 1.2" | 0.0" | 1.6 | 4.9 |
| October | 61°F (16°C) | 32°F (0°C) | 46°F (8°C) | 1.2" | 1.0" | 12.2 | 0.1 |
| November | 47°F (8°C) | 22°F (-6°C) | 34°F (1°C) | 0.5" | 2.8" | 23.8 | 0.0 |
| December | 37°F (3°C) | 14°F (-10°C) | 26°F (-4°C) | 0.4" | 5.6" | 28.7 | 0.0 |
The year, day by day
Roundup works both ends of the calendar. Normal highs climb to 91°F by July 27 and hold at or above 90°F on 22 dates, then normal lows drop to freezing or below on 194 dates, bottoming at 12°F around January 1.
When the heat sits
Normal highs reach 90°F from July 18 through August 8, covering 22 dates. The broader mild season, normal highs of 70°F or more, runs May 19 to September 29.
This counts calendar dates whose 1991–2020 normal high reaches 90°F. It is a smaller number than the 90°F+ day counts in the monthly table above, which measure how often the threshold was actually crossed in a typical year. A date can average 88°F and still exceed 90°F in half of all years.
The freezing stretch
The normal low stays at or below 32°F into April 25, then returns to freezing around October 15, covering 194 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 June 1, when 37% of years recorded at least a hundredth of an inch. The driest is January 31 at 12%. Summed across the calendar, that is about 74 wet dates a year.
The widest day
August 19 carries the biggest normal gap between afternoon and dawn, 37°F between the normal high and the normal low.
Look up any date
Any date's 1991–2020 normal for Roundup.
Where Roundup Stands Nationally
Day-to-night contrast is extreme by national standards — the widest normal daily swing reaches about 37°F, sharper than nine in ten ranked stations see.
Freezing is routine here by normals standards — the normal low reaches 32°F or colder on about 194 nights a year, more than most ranked stations.
Roundup 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: 5.2"
4.0 days with precipitation
Snow: 3.9"
3.6 days with precipitation
Snow: 4.4"
5.1 days with precipitation
Snow: 1.4"
7.7 days with precipitation
Snow: 0.1"
10.0 days with precipitation
10.6 days with precipitation
7.0 days with precipitation
5.1 days with precipitation
5.3 days with precipitation
Snow: 1.0"
6.9 days with precipitation
Snow: 2.8"
3.9 days with precipitation
Snow: 5.6"
4.5 days with precipitation
Roundup runs a summer-peaked wet season
39% of Roundup'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 2.9", on a wide 46.1°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, April, taking 48% of the annual total between them.
- Driest month: January at 0.4".
- Winter share: 8% 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.
How Roundup's precipitation splits across the calendar
About 74 days a year record measurable precipitation here, carrying 14.9" between them, or roughly 0.20 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 Roundup
Roundup averages 24.4 inches of snowfall a year, with December the snowiest month on the normals, spread across roughly 14 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: 24.4 inches of depth.
- Days recording measurable snow: about 14 a year.
- At a rough ten-to-one melt ratio, snow accounts for on the order of 16% 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 21
50% probability date
Last Spring Freeze
May 20
50% probability date
Growing Season
124 days
Heating & Cooling Degree Days
Annual totals indicate energy demand for heating and cooling
Heating Degree Days
7,193
Higher = more heating needed
Cooling Degree Days
482
Higher = more cooling needed
Warmest Month
July
Coldest Month
January
Nationwide similar cities
Other rankable U.S. places outside MT closest to Roundup 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 (47°F here).
- Beulah, MI 47°F · 0.0°F off
- Charles City, IA 47°F · 0.0°F off
- Coggon, IA 47°F · 0.0°F off
- Fort Dodge, IA 47°F · 0.0°F off
Closest by annual precipitation
Nearest out-of-state peers by annual precipitation (14.9" here), excluding temperature-peer places.
- Lamoille, NV 14.9" · 0.0" off
- Dillon, CO 14.9" · 0.0" off
- Trinidad, CO 14.9" · 0.0" off
- Laketown, UT 14.9" · 0.0" off
Snow and freeze rhythm
When cold and snow define Roundup
heating led · dry · mid swing
Roundup's energy balance leans toward cold weather: 7,193 annual heating degree days against 482 for cooling. Its 46.1°F seasonal range still makes the monthly rows more useful than the annual average alone.
Only about 124 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. Roundup coldest normal
January
Averaging 25°F (-4°C), this month sits below freezing for the month as a whole, not merely overnight.
-
2. Roundup typical freeze period
January through December
The station reports average freezing days from January through December.
-
3. Roundup snow peak
December
Roundup averages 24.4 inches of snow a year, with December the snowiest month on the normals.
Questions about Roundup's climate
How much snow does Roundup get? ▼
How many days above 90°F does Roundup get? ▼
How much energy does heating and cooling require in Roundup? ▼
Data Sources
Data source: NOAA U.S. Climate Normals v1.0.1 (1991-2020). All figures on this page are from Roundup's primary station: ROUNDUP (USC00247214). 2 NOAA stations are mapped to the Roundup 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 3064525). Match rule for Roundup: 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 Roundup 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.