Sumner Weather Forecast

    • 68
    • 89

    Slight Chance Thunderstorms

    • 66
    • 86

    Partly Sunny

    • 63
    • 80

    Chance Rain Showers

    • 66
    • 79

    Mostly Cloudy

    • 68
    • 86

    Rain Showers Likely

    • 63
    • 84

    Chance Rain Showers

Today 4 Sep Bremer

Mostly sunny. A slight chance of Showers and Thunderstorms in the morning. Humid with Highs around 90. South Winds 5 to 10 Mph. Chance of rain 20 percent. Heat index Values up to 102 in the afternoon.

Tonight 4 Sep Bremer

Mostly clear with a slight chance of Showers and Thunderstorms. Near steady temperature in the lower 70s. South Winds 5 to 10 Mph. Chance of rain 20 percent.

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  • Temperature Forecast NOAA

  • Temperature Real-Time

Sumner Temperature Statistics

September Temperature

Oelwein Municipal Airport (12.4 miles)

  • Lowest 1 September, 2026

    69.8 °F

  • Average September

    78.5 °F

  • Highest 1 September, 2026

    87.8 °F

Climate (2021–2026)

Oelwein Municipal Airport (12.4 miles)

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  • Average Low 2021–2026

    38.4 °F

  • Average 2021–2026

    48.1 °F

  • Average High 2021–2026

    57.9 °F
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