Sleepy Hollow weather by month
What a typical year looks like in Sleepy Hollow, Wyoming: average highs and lows, rain and snow, and the warmest and coldest days on record. Normals are the 1991–2020 averages at GILLETTE 3SE, 4 km from Sleepy Hollow; records cover 1902–2026.
The year at a glance
- Precipitation a year
- 17.6 in447 mm
- Snow a year
- 56 in141 cm
- Last spring freeze
- May 17
- First fall freeze
- Sep 21
- Heating degree days
- 7,158
- Cooling degree days
- 571
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 97°36° (cooling, 1%).
Month by month
Sleepy Hollow in January
Highs average 36°2° and lows 16°−9°, with 0.59 in15 mm of precipitation and 8 in21 cm of snow in a typical January.
- Record high
- 67°19° (1981)
- Record low
- −36°−38° (1930)
- Heating degree days
- 1209
- Cooling degree days
- 0
Sleepy Hollow in February
Highs average 38°3° and lows 17°−8°, with 0.78 in20 mm of precipitation and 9 in23 cm of snow in a typical February.
- Record high
- 70°21° (1982)
- Record low
- −40° (1936)
- Heating degree days
- 1058
- Cooling degree days
- 0
Sleepy Hollow in March
Highs average 49°9° and lows 25°−4°, with 1.1 in29 mm of precipitation and 9 in22 cm of snow in a typical March.
- Record high
- 82°28° (2026)
- Record low
- −23°−31° (1960)
- Heating degree days
- 876
- Cooling degree days
- 0
Sleepy Hollow in April
Highs average 56°14° and lows 32°0°, with 2.1 in54 mm of precipitation and 9 in24 cm of snow in a typical April.
- Record high
- 91°33° (1910)
- Record low
- −12°−24° (1936)
- Heating degree days
- 629
- Cooling degree days
- 0
Sleepy Hollow in May
Highs average 66°19° and lows 41°5°, with 3.3 in83 mm of precipitation and 1.3 in3.3 cm of snow in a typical May.
- Record high
- 95°35° (1934)
- Record low
- 11°−12° (1954)
- Heating degree days
- 369
- Cooling degree days
- 11
Sleepy Hollow in June
Highs average 77°25° and lows 50°10°, with 2.5 in65 mm of precipitation and 0.1 in0.3 cm of snow in a typical June.
- Record high
- 107°42° (2012)
- Record low
- 28°−2° (1969)
- Heating degree days
- 114
- Cooling degree days
- 72
Sleepy Hollow in July
Highs average 86°30° and lows 57°14°, with 1.7 in43 mm of precipitation in a typical July.
- Record high
- 110°43° (1909)
- Record low
- 35°2° (1968)
- Heating degree days
- 19
- Cooling degree days
- 227
Sleepy Hollow in August
Highs average 85°30° and lows 56°13°, with 1.4 in35 mm of precipitation in a typical August.
- Record high
- 106°41° (1949)
- Record low
- 31°−1° (1917)
- Heating degree days
- 29
- Cooling degree days
- 201
Sleepy Hollow in September
Highs average 75°24° and lows 46°8°, with 1.3 in32 mm of precipitation and 0.5 in1.3 cm of snow in a typical September.
- Record high
- 102°39° (1978)
- Record low
- 10°−12° (1926)
- Heating degree days
- 183
- Cooling degree days
- 58
Sleepy Hollow in OctoberThis month
Highs average 59°15° and lows 34°1°, with 1.6 in40 mm of precipitation and 4 in11 cm of snow in a typical October.
- Record high
- 98°37° (1922)
- Record low
- −12°−24° (1925)
- Heating degree days
- 566
- Cooling degree days
- 2
Sleepy Hollow in November
Highs average 46°8° and lows 24°−4°, with 0.63 in16 mm of precipitation and 6 in15 cm of snow in a typical November.
- Record high
- 81°27° (1908)
- Record low
- −26°−32° (1959)
- Heating degree days
- 896
- Cooling degree days
- 0
Sleepy Hollow in December
Highs average 36°2° and lows 16°−9°, with 0.64 in16 mm of precipitation and 8 in21 cm of snow in a typical December.
- Record high
- 72°22° (2021)
- Record low
- −37°−38° (1983)
- Heating degree days
- 1210
- Cooling degree days
- 0