Flagstaff Weather Forecast

    • 66
    • 92

    Chance Rain Showers

    • 64
    • 89

    Slight Chance Thunderstorms

    • 62
    • 86

    Slight Chance Thunderstorms

    • 61
    • 84

    Chance Thunderstorms

    • 62
    • 88

    Chance Rain Showers

    • 63
    • 89

    Slight Chance Thunderstorms

Today 6 Sep Boulder And Jefferson Counties Below 6000 Feet/West Broomfield County

Partly cloudy. Slight chance of Thunderstorms late in the afternoon. Highs 88 to 94. Chance of precipitation 20 percent.

Tonight 6 Sep Boulder And Jefferson Counties Below 6000 Feet/West Broomfield County

Mostly cloudy with a chance of Showers and slight chance of Thunderstorms in the Evening, then partly cloudy after midnight. Lows in the lower to mid 60s. Chance of rain 30 percent.

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  • Temperature Forecast NOAA

  • Temperature Real-Time

Flagstaff Temperature Statistics

September Temperature

Boulder Municipal Airport (3.7 miles)

  • Lowest 3 September, 2026

    59 °F

  • Average September

    75.8 °F

  • Highest 4 September, 2026

    95 °F

Climate (2021–2026)

Boulder Municipal Airport (3.7 miles)

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  • Average Low 2021–2026

    41.3 °F

  • Average 2021–2026

    53.7 °F

  • Average High 2021–2026

    66.4 °F
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