Union Square Weather Forecast

    • 51
    • 73

    Slight Chance Rain Showers

    • 53
    • 83

    Increasing Clouds

    • 50
    • 75

    Chance Thunderstorms

    • 49
    • 67

    Chance Thunderstorms

    • 49
    • 73

    Slight Chance Thunderstorms

    • 52
    • 76

    Partly Sunny

    • 54
    • 78

    Slight Chance Thunderstorms

Today 14 Sep Boulder And Jefferson Counties Below 6000 Feet/West Broomfield County

Mostly cloudy in the Morning, then becoming partly cloudy. Chance of Showers in the Morning, then a slight chance of Thunderstorms in the afternoon. Highs in the mid 70s. Chance of rain 40 percent.

Tonight 14 Sep Boulder And Jefferson Counties Below 6000 Feet/West Broomfield County

Mostly clear. Lows near 50.

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Union Square Temperature Statistics

September Temperature

Broomfield / Jeffco (12.4 miles)

  • Lowest 6 September, 2025

    48.2 °F

  • Average September

    67.1 °F

  • Highest 10 September, 2025

    91.4 °F

Climate (2020–Present)

Broomfield / Jeffco (12.4 miles)

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  • Average Low 2020–2025

    41.3 °F

  • Average 2020–2025

    50.6 °F

  • Average High 2020–2025

    64.9 °F
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