Twin Bridges, Montana climate: Normal weather by month, frost dates and records
Twin Bridges's normal year runs from 12°F December nights to 85°F July afternoons, with 9.4 inches of precipitation a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 6.4°C, December lows of −11°C, July highs of 29°C, 240 mm of precipitation a year.
- NOAA stationTwin Bridges
- Station IDUSC00248430
- Location45.55°N 112.33°W
- Elevation4,625 ft (1,410 m)
- Population405
On October 23, the normal high in Twin Bridges is 56°F and the normal low 26°F, and the chance of measurable rain or snow is 18%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Twin Bridges.
- Jan 35° 13°
- Feb 40° 15°
- Mar 49° 22°
- Apr 57° 28°
- May 66° 36°
- Jun 75° 43°
- Jul 85° 46°
- Aug 83° 43°
- Sep 74° 37°
- Oct 59° 28°
- Nov 44° 19°
- Dec 35° 12°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
What is the weather like in Twin Bridges each month?
July is the warmest month, with normal highs of 85°F; December the coldest, with normal lows of 12°F. The most precipitation falls in June (2.17 in), the least in January (0.22 in).
| Month | High | Low | Mean | Precip. | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|
| January | 35°F | 13°F | 24.2°F | 0.22 | 3 | <1 | 30 | 9 h |
| February | 40°F | 15°F | 27.3°F | 0.22 | 4 | <1 | 27 | 10 h 20 min |
| March | 49°F | 22°F | 35.5°F | 0.37 | 5 | <1 | 27 | 11 h 50 min |
| April | 57°F | 28°F | 42.5°F | 0.85 | 8 | <1 | 21 | 13 h 30 min |
| May | 66°F | 36°F | 51.3°F | 1.70 | 11 | <1 | 9 | 14 h 50 min |
| June | 75°F | 43°F | 58.7°F | 2.17 | 12 | 1 | 1 | 15 h 40 min |
| July | 85°F | 46°F | 65.4°F | 0.89 | 6 | 9 | <1 | 15 h 20 min |
| August | 83°F | 43°F | 63.3°F | 0.75 | 7 | 7 | 1 | 14 h 10 min |
| September | 74°F | 37°F | 55.1°F | 0.88 | 6 | 1 | 10 | 12 h 40 min |
| October | 59°F | 28°F | 43.6°F | 0.73 | 6 | <1 | 22 | 11 h |
| November | 44°F | 19°F | 31.7°F | 0.33 | 5 | <1 | 27 | 9 h 30 min |
| December | 35°F | 12°F | 23.3°F | 0.33 | 5 | <1 | 30 | 8 h 40 min |
| Year (annual) | 59°F | 29°F | 43.5°F | 9.44 | 78 | 17 | 206 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | 2°C | −11°C | −4.3°C | 6 mm |
| February | 4°C | −9°C | −2.6°C | 6 mm |
| March | 10°C | −6°C | 1.9°C | 9 mm |
| April | 14°C | −2°C | 5.8°C | 22 mm |
| May | 19°C | 2°C | 10.7°C | 43 mm |
| June | 24°C | 6°C | 14.8°C | 55 mm |
| July | 29°C | 8°C | 18.6°C | 23 mm |
| August | 29°C | 6°C | 17.4°C | 19 mm |
| September | 23°C | 3°C | 12.8°C | 22 mm |
| October | 15°C | −2°C | 6.4°C | 19 mm |
| November | 7°C | −7°C | −0.2°C | 8 mm |
| December | 1°C | −11°C | −4.8°C | 8 mm |
NOAA publishes no 1991-2020 snowfall normal for this station. The nearest record that keeps one, Glen (18 miles away), gets 10 inches of snow in a normal year; elevation and distance can change that.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00248430; annual normals. Wet days: 0.01 inch or more; 90°F days and freezing nights: NOAA's day counts. Daylight: sunrise to sunset on the 15th, computed from the latitude.
When is the best weather to visit Twin Bridges?
Normal highs sit between 65°F and 85°F in May, June, July, August and September. Of those, September has the fewest days with rain (6).
That is a measurement, not a recommendation: it counts the months whose normal afternoon high sits between 65°F and 85°F, where a light layer is enough by day.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00248430.
When is the last frost in Twin Bridges?
In Twin Bridges, the last spring frost (32°F) comes after June 8 in half of years and after July 1 in one year in ten; the first autumn frost comes before September 2 in half of years and before August 16 in one year in ten.
Frost-free in half of yearsFrost in 1 to 9 years out of 10Frost most years
- Last spring frost, half of years after
- June 81 year in 10 after July 1; 9 in 10 after May 22
- First autumn frost, half of years before
- September 21 year in 10 before August 16; 9 in 10 before September 15
NOAA puts the median frost-free season at 82 days, and the season without a hard freeze (28°F) at 116 days.
A hard freeze (28°F) comes after May 20 in half of springs and before September 15 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Twin Bridges in zone 5a in ZIP code 59754, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, Twin Bridges's NOAA station is in zone 5a: the coldest night of a typical year reaches −19°F (28 complete years).
Frost dates for every NOAA station in Montana · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00248430; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026; the station zone: ACIS daily lows, 1991-2020. A 10% date means one year in ten has a frost after it in spring or before it in autumn.
How hot and how cold does it get in Twin Bridges?
In a normal year in Twin Bridges, 17 days a year reach 90°F, 206 nights fall to 32°F or colder and 78 days bring measurable precipitation.
- Days at 90°F or more
- 17a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 206a normal year
- Days that stay below freezing
- 33high of 32°F or less
- Days with 0.01 inch of precipitation
- 78a normal year
The highest temperature in this station's record (since 1955) is 101°F, on July 12, 2002; the lowest is −39°F, on January 26, 1957.
The wettest calendar year on that record is 1983, with 16.24 in; the snowiest season is 1950–51, with 18.4 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00248430; records: ACIS (NOAA Regional Climate Centers), station USC00248430. Records use complete months only; a month missing more than three days is left out.
How sunny is Twin Bridges?
Over a year 76% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Twin Bridges, 4.2 kWh per square metre a day. July is the sunniest month (85%) and December the cloudiest (65%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 70% | 1.7 |
| February | 73% | 2.8 |
| March | 73% | 4.0 |
| April | 70% | 5.1 |
| May | 70% | 5.9 |
| June | 76% | 6.8 |
| July | 85% | 7.3 |
| August | 84% | 6.2 |
| September | 80% | 4.7 |
| October | 73% | 3.0 |
| November | 68% | 1.9 |
| December | 65% | 1.4 |
Source: NASA POWER solar climatology, 2001-2020 (CERES SYN1deg). Satellite-based, for the 1-degree cell (about 100 km across) around the station, so it describes the area rather than the airport.
How much heating and cooling does Twin Bridges need?
A normal year in Twin Bridges brings 7,934 heating degree days, 48% more than the median U.S. place (5,373), and 118 cooling degree days, 87% fewer than the median (908). Nine months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 1,505 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,265 | 0 |
| February | 1,054 | 0 |
| March | 913 | 0 |
| April | 675 | 0 |
| May | 427 | 1 |
| June | 201 | 12 |
| July | 53 | 65 |
| August | 89 | 36 |
| September | 300 | 3 |
| October | 664 | 0 |
| November | 999 | 0 |
| December | 1,294 | 0 |
| Year (annual) | 7,934 | 118 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00248430. A degree day is one degree of a day's mean temperature below 65°F (heating) or above it (cooling); utilities use them to estimate energy use.
Has Twin Bridges been warmer than normal lately?
2025 averaged 45.1°F, 1.6°F above the 1991-2020 normal of 43.5°F. 2 of the 4 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 44.9°F | +1.4°F | 5.84 |
| 2022 | 42.5°F | −1.0°F | 7.77 |
| 2023 | 43.2°F | −0.3°F | 11.78 |
| 2025 | 45.1°F | +1.6°F | 10.33 |
Over 61 complete years from 1957 to 2025, the station's annual mean temperature rose at a fitted 1.7°F per century (+0.10°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: observed years: ACIS, station USC00248430; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Twin Bridges's climate compare?
Twin Bridges is warmer than 56 of the other 140 places with their own NOAA record in Montana, and wetter than 1. Across the 7,247 U.S. stations with normals, its annual mean of 43.5°F is warmer than 14%.
In the Köppen classification computed from these normals, Twin Bridges is BSk: cold semi-arid steppe. What the classes mean.
Places with the most similar year elsewhere
Measured month by month on the normal high, low and precipitation, among places of 20,000 or more people in other states:
Source: NOAA NCEI 1991-2020 normals for every station PlainClimate covers. Similarity: the root-mean-square difference of the 36 monthly figures, precipitation weighted so an inch counts like 6°F.
Which places near Twin Bridges share this climate record?
2 places have no NOAA station with 1991-2020 normals of their own, and this station is the nearest full record. A place's own climate can differ from these figures, by several degrees where it sits much higher or lower than the station, nearer the coast, or inside a large city's heat; for the larger places the next nearest records are named with their yearly mean, so the spread around them is visible, and places of 50,000 or more have their own page with NOAA's gridded normals.
- Silver Star, MT72 people · 10 mi N
- Mammoth, MT17 people · 17 mi NE
Source: Census Bureau 2024 Gazetteer (place centers) and Vintage 2024 population estimates. Distance and direction from the station to each place's center.
Questions about Twin Bridges's climate
What is the coldest month in Twin Bridges?
December, with a normal high of 35°F and a normal low of 12°F. The warmest is July (85°F by day, 46°F at night).
Does it snow in Twin Bridges?
Yes. NOAA publishes no 1991-2020 snowfall normal for Twin Bridges's NOAA station; the nearest record that keeps one, Glen (18 miles away), records 10 inches of snow in a normal year.
What is the rainiest month in Twin Bridges?
June, with 2.17 in of precipitation in a normal year; the driest is January with 0.22 in.
What plant hardiness zone is Twin Bridges in?
The USDA's 2023 map puts Twin Bridges in zone 5a in ZIP code 59754, the nearest ZIP area. By the same method at Twin Bridges's NOAA station, the coldest night of a typical year reaches −19°F (28 years, 1991-2020): zone 5a.
How late can frost come in Twin Bridges?
In half of years the last 32°F night comes after June 8; in one year in ten it comes after July 1. Waiting until July 1 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Montana climateThe statewide normals and every place in the state
- Laurin (2 mi NE), MT17 miles from this station, 43.0°F a year
- Glen, MT18 miles from this station, 42.5°F a year
- Dillon, MT23 miles from this station, 41.8°F a year
- Divide, MT25 miles from this station, 40.9°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made