Blackleaf, Montana climate: Climate normals at a NOAA weather station
Blackleaf's normal year runs from 9°F January nights to 80°F July afternoons. (NOAA 1991-2020 normals)
In metric: a yearly mean of 5.2°C, January lows of −13°C, July highs of 27°C.
- NOAA stationBlackleaf
- Station IDUSC00240877
- Location48.01°N 112.44°W
- Elevation4,235 ft (1,291 m)
On October 22, the normal high in Blackleaf is 53°F and the normal low 24°F.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Blackleaf.
- Jan 37° 9°
- Feb 38° 10°
- Mar 44° 17°
- Apr 53° 27°
- May 63° 33°
- Jun 69° 41°
- Jul 80° 46°
- Aug 80° 44°
- Sep 70° 37°
- Oct 56° 27°
- Nov 44° 18°
- Dec 37° 11°
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 Blackleaf each month?
July is the warmest month, with normal highs of 80°F; January the coldest, with normal lows of 9°F.
| Month | High | Low | Mean | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|
| January | 37°F | 9°F | 22.8°F | – | <1 | 29 | 8 h 50 min |
| February | 38°F | 10°F | 24.2°F | – | <1 | 26 | 10 h 10 min |
| March | 44°F | 17°F | 30.7°F | – | <1 | 28 | 11 h 50 min |
| April | 53°F | 27°F | 39.7°F | – | <1 | 22 | 13 h 40 min |
| May | 63°F | 33°F | 48.2°F | – | <1 | 12 | 15 h 10 min |
| June | 69°F | 41°F | 54.8°F | – | <1 | 2 | 16 h |
| July | 80°F | 46°F | 63.1°F | – | 5 | <1 | 15 h 40 min |
| August | 80°F | 44°F | 61.9°F | – | 4 | 1 | 14 h 20 min |
| September | 70°F | 37°F | 53.5°F | – | 1 | 8 | 12 h 40 min |
| October | 56°F | 27°F | 41.5°F | – | <1 | 22 | 11 h |
| November | 44°F | 18°F | 30.9°F | – | <1 | 27 | 9 h 20 min |
| December | 37°F | 11°F | 23.9°F | – | <1 | 29 | 8 h 20 min |
| Year (annual) | 56°F | 27°F | 41.3°F | – | 10 | 207 |
The same normals in °C and millimetres
| Month | High | Low | Mean |
|---|---|---|---|
| January | 3°C | −13°C | −5.1°C |
| February | 3°C | −12°C | −4.3°C |
| March | 7°C | −8°C | −0.7°C |
| April | 12°C | −3°C | 4.3°C |
| May | 17°C | 1°C | 9.0°C |
| June | 20°C | 5°C | 12.7°C |
| July | 27°C | 8°C | 17.3°C |
| August | 26°C | 7°C | 16.6°C |
| September | 21°C | 3°C | 11.9°C |
| October | 13°C | −3°C | 5.3°C |
| November | 7°C | −8°C | −0.6°C |
| December | 3°C | −12°C | −4.5°C |
NOAA publishes no 1991-2020 snowfall normal for this station. The nearest record that keeps one, Choteau (17 miles away), gets 48 inches of snow in a normal year; elevation and distance can change that.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00240877; 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 Blackleaf?
Normal highs sit between 65°F and 85°F in June, July, August and September.
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 USC00240877.
When is the last frost at Blackleaf?
In Blackleaf, the last spring frost (32°F) comes after June 9 in half of years and after July 2 in one year in ten; the first autumn frost comes before September 3 in half of years and before August 19 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 91 year in 10 after July 2; 9 in 10 after May 25
- First autumn frost, half of years before
- September 31 year in 10 before August 19; 9 in 10 before September 18
NOAA puts the median frost-free season at 86 days, and the season without a hard freeze (28°F) at 116 days.
A hard freeze (28°F) comes after May 23 in half of springs and before September 17 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Blackleaf in zone 4b in ZIP code 59467, the nearest ZIP area.
Frost dates for every NOAA station in Montana · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00240877; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026. 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 Blackleaf?
In a normal year in Blackleaf, 10 days a year reach 90°F and 207 nights fall to 32°F or colder.
- Days at 90°F or more
- 10a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 207a normal year
- Days that stay below freezing
- 41high of 32°F or less
Source: NOAA NCEI 1991-2020 annual normals, station USC00240877.
How sunny is it at Blackleaf?
Over a year 73% of the sunlight that would reach the ground under clear skies gets through the clouds at Blackleaf, 3.8 kWh per square metre a day. July is the sunniest month (86%) and December the cloudiest (62%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 65% | 1.3 |
| February | 73% | 2.4 |
| March | 68% | 3.5 |
| April | 68% | 4.7 |
| May | 69% | 5.6 |
| June | 73% | 6.3 |
| July | 86% | 7.1 |
| August | 82% | 5.8 |
| September | 76% | 4.1 |
| October | 69% | 2.5 |
| November | 62% | 1.4 |
| December | 62% | 1.0 |
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 Blackleaf record?
A normal year at Blackleaf brings 8,737 heating degree days, 63% more than the median U.S. place (5,373), and 109 cooling degree days, 88% fewer than the median (908). Ten months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 1,224 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,308 | 0 |
| February | 1,142 | 0 |
| March | 1,063 | 0 |
| April | 761 | 0 |
| May | 521 | 0 |
| June | 308 | 3 |
| July | 117 | 57 |
| August | 139 | 43 |
| September | 351 | 5 |
| October | 729 | 0 |
| November | 1,023 | 0 |
| December | 1,275 | 0 |
| Year (annual) | 8,737 | 109 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00240877. 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 Blackleaf's climate compare?
Blackleaf is warmer than 22 of the 141 places with their own NOAA record in Montana. Across the 7,247 U.S. stations with normals, its annual mean of 41.3°F is warmer than 8%.
Source: NOAA NCEI 1991-2020 normals for every station PlainClimate covers.
Which places near Blackleaf share this climate record?
3 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.
- Dupuyer, MT131 people · 12 mi N
- Rockport Colony, MT44 people · 4 mi NW
- Pendroy, MT13 people · 8 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 Blackleaf's climate
What is the coldest month at Blackleaf?
January, with a normal high of 37°F and a normal low of 9°F. The warmest is July (80°F by day, 46°F at night).
Does it snow at Blackleaf?
Yes. NOAA publishes no 1991-2020 snowfall normal for the station; the nearest record that keeps one, Choteau (17 miles away), records 48 inches of snow in a normal year.
What plant hardiness zone is Blackleaf in?
The USDA's 2023 map puts Blackleaf in zone 4b in ZIP code 59467, the nearest ZIP area.
How late can frost come at Blackleaf?
In half of years the last 32°F night comes after June 9; in one year in ten it comes after July 2. Waiting until July 2 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Montana climateThe statewide normals and every place in the state
- Bynum, MT9 miles from this station, 43.5°F a year
- Choteau, MT17 miles from this station, 43.8°F a year
- Valier, MT22 miles from this station, 44.1°F a year
- Conrad, MT25 miles from this station, 43.7°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made