Keystone Weather Forecast

    • 47
    • 80

    Slight Chance Thunderstorms

    • 45
    • 75

    Slight Chance Thunderstorms

    • 44
    • 76

    Partly Sunny

    • 44
    • 78

    Mostly Sunny

    • 44
    • 77

    Mostly Sunny

    • 44
    • 76

    Mostly Sunny

    • 42
    • 75

    Chance Thunderstorms

Today 6 Sep South and Southeast Grand/West Central and Southwest Boulder/Gilpin/Clear Creek/Summit/North and Wes

Partly cloudy with a slight chance of Thunderstorms. Chance of Showers late in the afternoon. Highs 64 to 74. Chance of rain 30 percent.

Tonight 6 Sep South and Southeast Grand/West Central and Southwest Boulder/Gilpin/Clear Creek/Summit/North and Wes

Mostly cloudy with a slight chance of Thunderstorms early in the Evening, then mostly cloudy with a slight chance of Showers during the late evening hours. Partly cloudy after midnight. Lows 42 to 52. Chance of rain 20 percent.

Graph Plots Open in Graphs

  • Temperature Forecast NOAA

  • Temperature Real-Time

Keystone Temperature Statistics

September Temperature

Copper Mountain - Red Cliff Pass (13.7 miles)

  • Lowest 1 September, 2026

    39.2 °F

  • Average September

    47.4 °F

  • Highest 3 September, 2026

    60.8 °F

Climate (2021–2026)

Copper Mountain - Red Cliff Pass (13.7 miles)

Take a look at our website widgetsAvailable free! Find Out More

  • Average Low 2021–2026

    29.4 °F

  • Average 2021–2026

    35.8 °F

  • Average High 2021–2026

    42.1 °F
Get WillyWeather+ to remove ads