Thornton Weather Forecast

    • 54
    • 89

    Increasing Clouds

    • 51
    • 73

    Chance Thunderstorms

    • 55
    • 78

    Slight Chance Thunderstorms

    • 57
    • 80

    Chance Thunderstorms

    • 56
    • 84

    Slight Chance Thunderstorms

    • 57
    • 85

    Partly Sunny

Today 4 Sep North Douglas County Below 6000 Feet/Denver/West Adams and Arapahoe Counties/East Broomfield County

Mostly sunny. Highs in the upper 80s.

Tonight 4 Sep North Douglas County Below 6000 Feet/Denver/West Adams and Arapahoe Counties/East Broomfield County

Mostly cloudy. Slight chance of Thunderstorms in the Evening, then a slight chance of Showers after midnight. Lows in the lower 50s. Northeast Winds 10 to 15 Mph with Gusts up to 20 Mph. Chance of rain 20 percent.

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Thornton Temperature Statistics

September Temperature

Broomfield / Jeffco (6.8 miles)

  • Lowest 1 September, 2025

    57.2 °F

  • Average September

    67.5 °F

  • Highest 1 September, 2025

    84.2 °F

Climate (2020–Present)

Broomfield / Jeffco (6.8 miles)

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  • Average Low 2020–2025

    41.2 °F

  • Average 2020–2025

    50.6 °F

  • Average High 2020–2025

    64.8 °F
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