Casper weather by month
What a typical year looks like in Casper, Wyoming: average highs and lows, rain and snow, and the warmest and coldest days on record. Normals are the 1991–2020 averages at Casper-Natrona County Airport, 14 km from Casper; records cover 1939–2026.
The year at a glance
- Precipitation a year
- 12.2 in310 mm
- Snow a year
- 72 in182 cm
- Last spring freeze
- May 21
- First fall freeze
- Sep 20
- Heating degree days
- 7,486
- Cooling degree days
- 443
Freeze dates are medians (half of years earlier, half later). Degree days use a 65°F base; HVAC design temperatures here are −11°−24° (heating, 99%) and 98°37° (cooling, 1%).
Month by month
Casper in January
Highs average 35°2° and lows 15°−9°, with 0.49 in12 mm of precipitation and 9 in23 cm of snow in a typical January.
- Record high
- 60°16° (1971)
- Record low
- −40° (1949)
- Heating degree days
- 1237
- Cooling degree days
- 0
Casper in February
Highs average 38°3° and lows 15°−9°, with 0.56 in14 mm of precipitation and 11 in28 cm of snow in a typical February.
- Record high
- 68°20° (1982)
- Record low
- −32°−36° (2006)
- Heating degree days
- 1075
- Cooling degree days
- 0
Casper in March
Highs average 49°9° and lows 23°−5°, with 0.84 in21 mm of precipitation and 10 in26 cm of snow in a typical March.
- Record high
- 83°28° (2026)
- Record low
- −25°−32° (2022)
- Heating degree days
- 907
- Cooling degree days
- 0
Casper in April
Highs average 56°13° and lows 28°−2°, with 1.4 in36 mm of precipitation and 11 in27 cm of snow in a typical April.
- Record high
- 84°29° (1992)
- Record low
- −6°−21° (1997)
- Heating degree days
- 682
- Cooling degree days
- 0
Casper in May
Highs average 67°19° and lows 37°3°, with 2.2 in56 mm of precipitation and 2.6 in6.6 cm of snow in a typical May.
- Record high
- 95°35° (2003)
- Record low
- 16°−9° (1953)
- Heating degree days
- 409
- Cooling degree days
- 4
Casper in June
Highs average 80°26° and lows 45°7°, with 1.3 in34 mm of precipitation and 0.1 in0.3 cm of snow in a typical June.
- Record high
- 102°39° (1988)
- Record low
- 25°−4° (2019)
- Heating degree days
- 126
- Cooling degree days
- 51
Casper in July
Highs average 89°32° and lows 53°12°, with 1.2 in30 mm of precipitation in a typical July.
- Record high
- 104°40° (1954)
- Record low
- 30°−1° (1972)
- Heating degree days
- 14
- Cooling degree days
- 200
Casper in August
Highs average 87°30° and lows 51°11°, with 0.79 in20 mm of precipitation in a typical August.
- Record high
- 103°39° (2026)
- Record low
- 29°−2° (2015)
- Heating degree days
- 31
- Cooling degree days
- 157
Casper in September
Highs average 76°24° and lows 42°6°, with 0.95 in24 mm of precipitation and 1.5 in3.8 cm of snow in a typical September.
- Record high
- 100°38° (2022)
- Record low
- 15°−9° (1945)
- Heating degree days
- 214
- Cooling degree days
- 30
Casper in OctoberThis month
Highs average 60°15° and lows 31°−1°, with 1.2 in30 mm of precipitation and 7 in18 cm of snow in a typical October.
- Record high
- 87°31° (1992)
- Record low
- −9°−23° (2019)
- Heating degree days
- 611
- Cooling degree days
- 1
Casper in November
Highs average 46°8° and lows 22°−6°, with 0.64 in16 mm of precipitation and 9 in23 cm of snow in a typical November.
- Record high
- 73°23° (2020)
- Record low
- −27°−33° (2014)
- Heating degree days
- 932
- Cooling degree days
- 0
Casper in December
Highs average 35°2° and lows 15°−10°, with 0.61 in15 mm of precipitation and 11 in28 cm of snow in a typical December.
- Record high
- 66°19° (2021)
- Record low
- −42°−41° (2022)
- Heating degree days
- 1248
- Cooling degree days
- 0