Keystone weather by month
What a typical year looks like in Keystone, Colorado: average highs and lows, rain and snow, and the warmest and coldest days on record. Normals are the 1991–2020 averages at GEORGETOWN, 25 km from Keystone; records cover 1893–2026.
The year at a glance
- Precipitation a year
- 18.3 in465 mm
- Snow a year
- 106 in269 cm
- Last spring freeze
- Jun 8
- First fall freeze
- Sep 18
- Heating degree days
- 8,311
- Cooling degree days
- 41
Freeze dates are medians (half of years earlier, half later). Degree days use a 65°F base; HVAC design temperatures here are −4°−20° (heating, 99%) and 85°29° (cooling, 1%).
Month by month
Keystone in January
Highs average 36°2° and lows 16°−9°, with 0.81 in21 mm of precipitation and 13 in32 cm of snow in a typical January.
- Record high
- 60°16° (1959)
- Record low
- −28°−33° (1972)
- Heating degree days
- 1211
- Cooling degree days
- 0
Keystone in February
Highs average 38°3° and lows 15°−9°, with 0.9 in23 mm of precipitation and 13 in32 cm of snow in a typical February.
- Record high
- 62°17° (1950)
- Record low
- −25°−32° (2011)
- Heating degree days
- 1078
- Cooling degree days
- 0
Keystone in March
Highs average 45°7° and lows 21°−6°, with 1.4 in35 mm of precipitation and 19 in47 cm of snow in a typical March.
- Record high
- 74°23° (2026)
- Record low
- −15°−26° (1899)
- Heating degree days
- 998
- Cooling degree days
- 0
Keystone in April
Highs average 50°10° and lows 26°−3°, with 2.3 in59 mm of precipitation and 21 in53 cm of snow in a typical April.
- Record high
- 76°24° (1960)
- Record low
- −8°−22° (1997)
- Heating degree days
- 813
- Cooling degree days
- 0
Keystone in May
Highs average 60°15° and lows 35°1°, with 2.1 in54 mm of precipitation and 7 in17 cm of snow in a typical May.
- Record high
- 83°28° (2002)
- Record low
- 7°−14° (2013)
- Heating degree days
- 555
- Cooling degree days
- 0
Keystone in June
Highs average 72°22° and lows 42°6°, with 1.5 in39 mm of precipitation and 0.2 in0.5 cm of snow in a typical June.
- Record high
- 92°33° (1954)
- Record low
- 24°−4° (1951)
- Heating degree days
- 244
- Cooling degree days
- 6
Keystone in July
Highs average 77°25° and lows 49°9°, with 2.5 in63 mm of precipitation in a typical July.
- Record high
- 92°33° (1954)
- Record low
- 31°−1° (1971)
- Heating degree days
- 89
- Cooling degree days
- 25
Keystone in August
Highs average 75°24° and lows 47°8°, with 2.2 in55 mm of precipitation in a typical August.
- Record high
- 89°32° (2002)
- Record low
- 29°−2° (2004)
- Heating degree days
- 149
- Cooling degree days
- 10
Keystone in September
Highs average 68°20° and lows 39°4°, with 1.5 in39 mm of precipitation and 1.6 in4.1 cm of snow in a typical September.
- Record high
- 86°30° (1960)
- Record low
- 8°−13° (1971)
- Heating degree days
- 336
- Cooling degree days
- 0
Keystone in OctoberThis month
Highs average 57°14° and lows 30°−1°, with 1.3 in32 mm of precipitation and 8 in19 cm of snow in a typical October.
- Record high
- 81°27° (2010)
- Record low
- −4°−20° (1972)
- Heating degree days
- 666
- Cooling degree days
- 0
Keystone in November
Highs average 44°7° and lows 22°−6°, with 0.89 in23 mm of precipitation and 11 in28 cm of snow in a typical November.
- Record high
- 70°21° (1999)
- Record low
- −16°−27° (2014)
- Heating degree days
- 958
- Cooling degree days
- 0
Keystone in December
Highs average 36°2° and lows 15°−9°, with 0.86 in22 mm of precipitation and 14 in37 cm of snow in a typical December.
- Record high
- 62°17° (2021)
- Record low
- −17°−27° (2005)
- Heating degree days
- 1214
- Cooling degree days
- 0
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