National City Weather Forecast

    • 61
    • 90

    Mostly Sunny

    • 72
    • 97

    Hot

    • 72
    • 100

    Rain Showers

    • 64
    • 86

    Partly Sunny

    • 69
    • 89

    Chance Rain Showers

    • 70
    • 93

    Slight Chance Thunderstorms

Today 7 Sep St. Clair

Partly sunny this Morning, then clearing. Highs in the upper 80s. East Winds 5 to 10 Mph.

Tonight 7 Sep St. Clair

Mostly clear. Lows in the lower 60s. East Winds 5 to 10 Mph.

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  • Temperature Forecast NOAA

  • Temperature Real-Time

National City Temperature Statistics

September Temperature

St. Louis Downtown Airport (5.6 miles)

  • Lowest 1 September, 2026

    70.6 °F

  • Average September

    86.7 °F

  • Highest 5 September, 2026

    100.9 °F

Climate (2021–2026)

St. Louis Downtown Airport (5.6 miles)

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  • Average Low 2021–2026

    47.7 °F

  • Average 2021–2026

    58.6 °F

  • Average High 2021–2026

    69.4 °F
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