St Mary's Weather Forecast

    • 35
    • 48

    Rain Showers

    • 38
    • 46

    Chance Rain/Snow

    • 40
    • 54

    Partly Sunny

    • 35
    • 51

    Chance Thunderstorms

    • 36
    • 50

    Chance Thunderstorms

    • 40
    • 54

    Mostly Sunny

Today 13 Sep South and Southeast Grand/West Central and Southwest Boulder/Gilpin/Clear Creek/Summit/North and Wes

Chance of rain Showers, snow Showers and slight chance of Thunderstorms in the Morning, then rain Showers with Thunderstorms likely and snow Showers in the afternoon. No snow accumulation. Highs 48 to 58.

Tonight 13 Sep South and Southeast Grand/West Central and Southwest Boulder/Gilpin/Clear Creek/Summit/North and Wes

Rain Showers, snow Showers likely and chance of Thunderstorms in the Evening, then a chance of rain and snow Showers after midnight. Snow accumulation up to 1 inch. Lows 29 to 39. West Winds 10 to 15 Mph with Gusts up to 20 Mph after midnight. Chance of precipitation 60 percent.

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St Mary's Temperature Statistics

September Temperature

Boulder Municipal Airport (26.7 miles)

  • Lowest 6 September, 2025

    44.6 °F

  • Average September

    69.4 °F

  • Highest 10 September, 2025

    91.4 °F

Climate (2020–Present)

Boulder Municipal Airport (26.7 miles)

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  • Average Low 2020–2025

    40.4 °F

  • Average 2020–2025

    52.6 °F

  • Average High 2020–2025

    65 °F
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