Shelby weather by month
What a typical year looks like in Shelby, Montana: average highs and lows, rain and snow, and the warmest and coldest days on record. Normals are the 1991–2020 averages at Shelby, 1 km from Shelby; records cover 1950–2026.
The year at a glance
- Precipitation a year
- 12.1 in308 mm
- Snow a year
- 39 in99 cm
- Last spring freeze
- May 20
- First fall freeze
- Sep 19
- Heating degree days
- 8,532
- Cooling degree days
- 241
Freeze dates are medians (half of years earlier, half later). Degree days use a 65°F base; HVAC design temperatures here are −22°−30° (heating, 99%) and 95°35° (cooling, 1%).
Month by month
Shelby in January
Highs average 31°0° and lows 6°−14°, with 0.46 in12 mm of precipitation and 7 in19 cm of snow in a typical January.
- Record high
- 69°21° (2015)
- Record low
- −44°−42° (1954)
- Heating degree days
- 1434
- Cooling degree days
- 0
Shelby in February
Highs average 35°2° and lows 10°−12°, with 0.36 in9.1 mm of precipitation and 6 in15 cm of snow in a typical February.
- Record high
- 69°21° (1954)
- Record low
- −37°−38° (1996)
- Heating degree days
- 1187
- Cooling degree days
- 0
Shelby in March
Highs average 44°7° and lows 18°−8°, with 0.63 in16 mm of precipitation and 7 in18 cm of snow in a typical March.
- Record high
- 78°26° (2004)
- Record low
- −37°−38° (1951)
- Heating degree days
- 1049
- Cooling degree days
- 0
Shelby in April
Highs average 54°12° and lows 28°−2°, with 1.3 in34 mm of precipitation and 4 in10 cm of snow in a typical April.
- Record high
- 86°30° (1952)
- Record low
- −9°−23° (2018)
- Heating degree days
- 711
- Cooling degree days
- 0
Shelby in May
Highs average 64°18° and lows 38°3°, with 1.8 in45 mm of precipitation and 1.9 in4.8 cm of snow in a typical May.
- Record high
- 91°33° (2001)
- Record low
- 12°−11° (1954)
- Heating degree days
- 431
- Cooling degree days
- 4
Shelby in June
Highs average 73°23° and lows 46°8°, with 2.9 in72 mm of precipitation in a typical June.
- Record high
- 97°36° (2002)
- Record low
- 30°−1° (2000)
- Heating degree days
- 190
- Cooling degree days
- 19
Shelby in July
Highs average 82°28° and lows 52°11°, with 1.1 in29 mm of precipitation in a typical July.
- Record high
- 102°39° (2007)
- Record low
- 36°2° (1952)
- Heating degree days
- 52
- Cooling degree days
- 109
Shelby in August
Highs average 82°28° and lows 49°10°, with 0.85 in22 mm of precipitation in a typical August.
- Record high
- 103°39° (2018)
- Record low
- 30°−1° (1950)
- Heating degree days
- 74
- Cooling degree days
- 97
Shelby in September
Highs average 71°22° and lows 41°5°, with 1 in26 mm of precipitation and 0.5 in1.3 cm of snow in a typical September.
- Record high
- 96°36° (1950)
- Record low
- 16°−9° (1955)
- Heating degree days
- 292
- Cooling degree days
- 12
Shelby in OctoberThis month
Highs average 56°13° and lows 29°−2°, with 0.74 in19 mm of precipitation and 1.4 in3.6 cm of snow in a typical October.
- Record high
- 89°32° (2011)
- Record low
- −12°−24° (2020)
- Heating degree days
- 695
- Cooling degree days
- 0
Shelby in November
Highs average 42°6° and lows 18°−8°, with 0.52 in13 mm of precipitation and 6 in14 cm of snow in a typical November.
- Record high
- 74°23° (2004)
- Record low
- −31°−35° (1955)
- Heating degree days
- 1056
- Cooling degree days
- 0
Shelby in December
Highs average 33°1° and lows 9°−13°, with 0.46 in12 mm of precipitation and 6 in14 cm of snow in a typical December.
- Record high
- 65°18° (1956)
- Record low
- −36°−38° (1996)
- Heating degree days
- 1361
- Cooling degree days
- 0