Alder (17 mi S), Montana climate: Climate normals at a NOAA weather station
Alder (17 mi S)'s normal year runs from 14°F December nights to 80°F July afternoons, with 14.1 inches of precipitation and 57 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 5.8°C, December lows of −10°C, July highs of 27°C, 357 mm of precipitation a year.
- NOAA stationAlder (17 mi S)
- Station IDUSC00240110
- Location45.07°N 112.06°W
- Elevation5,850 ft (1,783 m)
On October 22, the normal high in Alder (17 mi S) is 52°F and the normal low 29°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 Alder (17 mi S).
- Jan 34° 16°
- Feb 36° 16°
- Mar 45° 23°
- Apr 52° 29°
- May 62° 36°
- Jun 69° 42°
- Jul 80° 48°
- Aug 80° 47°
- Sep 69° 39°
- Oct 55° 31°
- Nov 42° 21°
- Dec 33° 14°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
What is the weather like at Alder (17 mi S) each month?
July is the warmest month, with normal highs of 80°F; December the coldest, with normal lows of 14°F. The most precipitation falls in June (2.97 in), the least in January (0.29 in).
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 34°F | 16°F | 24.7°F | 0.29 | 8.2 | 5 | <1 | 30 | 9 h 10 min |
| February | 36°F | 16°F | 25.9°F | 0.55 | 7.5 | 5 | <1 | 27 | 10 h 20 min |
| March | 45°F | 23°F | 34.0°F | 0.58 | 8.4 | 5 | <1 | 27 | 11 h 50 min |
| April | 52°F | 29°F | 40.5°F | 1.28 | 9.7 | 9 | <1 | 21 | 13 h 30 min |
| May | 62°F | 36°F | 48.7°F | 2.37 | 3.6 | 12 | <1 | 9 | 14 h 50 min |
| June | 69°F | 42°F | 55.9°F | 2.97 | 0.1 | 11 | <1 | 2 | 15 h 40 min |
| July | 80°F | 48°F | 64.2°F | 1.17 | 0.0 | 7 | 3 | <1 | 15 h 20 min |
| August | 80°F | 47°F | 63.7°F | 1.24 | 0.0 | 7 | 2 | <1 | 14 h 10 min |
| September | 69°F | 39°F | 54.2°F | 1.23 | 0.2 | 5 | <1 | 5 | 12 h 40 min |
| October | 55°F | 31°F | 42.8°F | 1.29 | 3.1 | 6 | <1 | 18 | 11 h |
| November | 42°F | 21°F | 31.4°F | 0.61 | 8.0 | 5 | <1 | 25 | 9 h 40 min |
| December | 33°F | 14°F | 23.6°F | 0.48 | 8.4 | 5 | <1 | 29 | 8 h 50 min |
| Year (annual) | 55°F | 30°F | 42.5°F | 14.06 | 57.2 | 81 | 5 | 193 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | 1°C | −9°C | −4.1°C | 7 mm | 21 cm |
| February | 2°C | −9°C | −3.4°C | 14 mm | 19 cm |
| March | 7°C | −5°C | 1.1°C | 15 mm | 21 cm |
| April | 11°C | −2°C | 4.7°C | 33 mm | 25 cm |
| May | 16°C | 2°C | 9.3°C | 60 mm | 9 cm |
| June | 21°C | 6°C | 13.3°C | 75 mm | 0 cm |
| July | 27°C | 9°C | 17.9°C | 30 mm | 0 cm |
| August | 27°C | 8°C | 17.6°C | 31 mm | 0 cm |
| September | 21°C | 4°C | 12.3°C | 31 mm | 1 cm |
| October | 13°C | −1°C | 6.0°C | 33 mm | 8 cm |
| November | 5°C | −6°C | −0.3°C | 15 mm | 20 cm |
| December | 1°C | −10°C | −4.7°C | 12 mm | 21 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00240110; 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.
Which months are mildest at Alder (17 mi S)?
Normal highs sit between 65°F and 85°F in June, July, August and September. Of those, September has the fewest days with rain (5).
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 USC00240110.
When is the last frost at Alder (17 mi S)?
In Alder (17 mi S), the last spring frost (32°F) comes after June 6 in half of years and after June 25 in one year in ten; the first autumn frost comes before September 14 in half of years and before August 31 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 61 year in 10 after June 25; 9 in 10 after May 20
- First autumn frost, half of years before
- September 141 year in 10 before August 31; 9 in 10 before September 27
NOAA puts the median frost-free season at 98 days, and the season without a hard freeze (28°F) at 131 days.
A hard freeze (28°F) comes after May 16 in half of springs and before September 26 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Alder (17 mi S) in zone 5a in ZIP code 59710, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, the station is in zone 5a: the coldest night of a typical year reaches −19°F (17 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 USC00240110; 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 at Alder (17 mi S)?
In a normal year in Alder (17 mi S), 5 days a year reach 90°F, 193 nights fall to 32°F or colder and 81 days bring measurable precipitation.
- Days at 90°F or more
- 5a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 193a normal year
- Days that stay below freezing
- 47high of 32°F or less
- Days with 0.01 inch of precipitation
- 81a normal year
- Days with 1 inch of snow or more
- 19a normal year
The highest temperature in this station's record (since 1956) is 97°F, on August 4, 1961; the lowest is −41°F, on December 23, 1983.
The wettest calendar year on that record is 2005, with 19.39 in; the snowiest season is 1994–95, with 88.2 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00240110; records: ACIS (NOAA Regional Climate Centers), station USC00240110. Records use complete months only; a month missing more than three days is left out.
How sunny is it at Alder (17 mi S)?
Over a year 76% of the sunlight that would reach the ground under clear skies gets through the clouds at Alder (17 mi S), 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 many heating and cooling degree days does Alder (17 mi S) record?
A normal year at Alder (17 mi S) brings 8,319 heating degree days, 55% more than the median U.S. place (5,373), and 130 cooling degree days, 86% 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 1,366 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,251 | 0 |
| February | 1,096 | 0 |
| March | 961 | 0 |
| April | 733 | 0 |
| May | 506 | 1 |
| June | 282 | 7 |
| July | 90 | 63 |
| August | 93 | 54 |
| September | 330 | 6 |
| October | 687 | 0 |
| November | 1,008 | 0 |
| December | 1,283 | 0 |
| Year (annual) | 8,319 | 130 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00240110. 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.
How does Alder (17 mi S)'s climate compare?
Alder (17 mi S) is warmer than 38 of the 141 places with their own NOAA record in Montana, and wetter than 49. Across the 7,247 U.S. stations with normals, its annual mean of 42.5°F is warmer than 11%.
In the Köppen classification computed from these normals, Alder (17 mi S) 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.
Questions about Alder (17 mi S)'s climate
What is the coldest month at Alder (17 mi S)?
December, with a normal high of 33°F and a normal low of 14°F. The warmest is July (80°F by day, 48°F at night).
Does it snow at Alder (17 mi S)?
Yes: 57 inches in a normal year, falling on 33 days with 0.1 inch or more, the most in April (9.7 inches).
What is the rainiest month at Alder (17 mi S)?
June, with 2.97 in of precipitation in a normal year; the driest is January with 0.29 in.
What plant hardiness zone is Alder (17 mi S) in?
The USDA's 2023 map puts Alder (17 mi S) in zone 5a in ZIP code 59710, the nearest ZIP area. By the same method at the station, the coldest night of a typical year reaches −19°F (17 years, 1991-2020): zone 5a.
How late can frost come at Alder (17 mi S)?
In half of years the last 32°F night comes after June 6; in one year in ten it comes after June 25. Waiting until June 25 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Montana climateThe statewide normals and every place in the state
- Alder (19 mi S), MT2 miles from this station, 40.8°F a year
- Virginia City, MT16 miles from this station, 43.9°F a year
- Laurin (2 mi NE), MT21 miles from this station, 43.0°F a year
- Ennis, MT25 miles from this station, 42.7°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made