Corvallis weather by month
What a typical year looks like in Corvallis, Montana: average highs and lows, rain and snow, and the warmest and coldest days on record. Normals are the 1991–2020 averages at Stevensville, 22 km from Corvallis; records cover 1911–2026.
The year at a glance
- Precipitation a year
- 12.5 in316 mm
- Snow a year
- 17 in43 cm
- Last spring freeze
- May 21
- First fall freeze
- Sep 14
- Heating degree days
- 7,272
- Cooling degree days
- 217
Freeze dates are medians (half of years earlier, half later). Degree days use a 65°F base; HVAC design temperatures here are −5°−21° (heating, 99%) and 97°36° (cooling, 1%).
Month by month
Corvallis in January
Highs average 35°1° and lows 19°−7°, with 1 in25 mm of precipitation and 4 in10 cm of snow in a typical January.
- Record high
- 63°17° (1992)
- Record low
- −36°−38° (1957)
- Heating degree days
- 1186
- Cooling degree days
- 0
Corvallis in February
Highs average 38°3° and lows 21°−6°, with 0.92 in23 mm of precipitation and 3 in8 cm of snow in a typical February.
- Record high
- 70°21° (1932)
- Record low
- −37°−38° (1936)
- Heating degree days
- 987
- Cooling degree days
- 0
Corvallis in March
Highs average 50°10° and lows 26°−3°, with 0.77 in20 mm of precipitation and 1.5 in3.8 cm of snow in a typical March.
- Record high
- 80°27° (2004)
- Record low
- −19°−28° (1922)
- Heating degree days
- 839
- Cooling degree days
- 0
Corvallis in April
Highs average 58°14° and lows 32°0°, with 0.93 in24 mm of precipitation and 0.1 in0.3 cm of snow in a typical April.
- Record high
- 88°31° (1977)
- Record low
- 2°−17° (1936)
- Heating degree days
- 600
- Cooling degree days
- 0
Corvallis in May
Highs average 68°20° and lows 39°4°, with 1.5 in37 mm of precipitation in a typical May.
- Record high
- 98°37° (1936)
- Record low
- 15°−9° (2001)
- Heating degree days
- 369
- Cooling degree days
- 3
Corvallis in June
Highs average 75°24° and lows 45°7°, with 1.6 in40 mm of precipitation in a typical June.
- Record high
- 104°40° (2003)
- Record low
- 27°−3° (1946)
- Heating degree days
- 171
- Cooling degree days
- 24
Corvallis in July
Highs average 85°30° and lows 49°9°, with 0.83 in21 mm of precipitation in a typical July.
- Record high
- 107°42° (2003)
- Record low
- 30°−1° (1931)
- Heating degree days
- 42
- Cooling degree days
- 108
Corvallis in August
Highs average 84°29° and lows 47°8°, with 0.81 in21 mm of precipitation in a typical August.
- Record high
- 104°40° (1961)
- Record low
- 27°−3° (1992)
- Heating degree days
- 58
- Cooling degree days
- 74
Corvallis in September
Highs average 74°23° and lows 40°5°, with 0.84 in21 mm of precipitation in a typical September.
- Record high
- 98°37° (1967)
- Record low
- 7°−14° (1926)
- Heating degree days
- 248
- Cooling degree days
- 8
Corvallis in OctoberThis month
Highs average 58°14° and lows 32°0°, with 1 in26 mm of precipitation and 0.1 in0.3 cm of snow in a typical October.
- Record high
- 87°31° (2010)
- Record low
- −3°−19° (2020)
- Heating degree days
- 618
- Cooling degree days
- 0
Corvallis in November
Highs average 43°6° and lows 25°−4°, with 1.2 in29 mm of precipitation and 1.6 in4.1 cm of snow in a typical November.
- Record high
- 74°23° (1999)
- Record low
- −28°−33° (1955)
- Heating degree days
- 945
- Cooling degree days
- 0
Corvallis in December
Highs average 33°1° and lows 19°−7°, with 1.1 in28 mm of precipitation and 7 in17 cm of snow in a typical December.
- Record high
- 65°18° (2021)
- Record low
- −36°−38° (1927)
- Heating degree days
- 1209
- Cooling degree days
- 0