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      Extreme Heat Warning
      until 8:00 PM CDT
      Elev 597 ft, 38.781 °N 90.711 °W

      O'Fallon, MO

      O'Fallon Station79°
      Updated: 7:21 AM CDT on September 4, 2026 (GMT -5)
      4 minutes ago
      100°
      76°
      79
      Feels Like 82
      Sunny
      N
      1
      Same temperature is expected today
      50
      50
      575
      90
      50
      7
      0 mph
      50
      50
      50
      50
      50
      50
      Radar · Now
        Hyper-local data from Weather Underground's network of
        400,000+ personal weather stations worldwide
        Today
        Sat 09/05
        High 100°f
         1% Precip. / 0 in
        Abundant sunshine. Very hot. High near 100F. Winds light and variable.
        Tonight
        Sat 09/05
        Low 75°f
         8% Precip. / 0 in
        Clear skies. Low near 75F. Winds light and variable.
        Tomorrow
        Sun 09/06
        High 100°f72°f
         9% Precip. / 0 in
        Mostly sunny skies. Very hot. High around 100F. Winds light and variable.
        Hourly Forecast
        Now
        77°
        8AM
        80°
        9AM
        85°
        10AM
        89°
        11AM
        92°
        12PM
        94°
        1PM
        95°
        2PM
        97°
        3PM
        98°
        4PM
        98°
        5PM
        98°
        6PM
        96°
        7PM
        93°
        7:28PM
        Sunset
        8PM
        87°
        9PM
        85°
        10PM
        83°
        11PM
        82°
        12AM
        81°
        1AM
        79°
        2AM
        79°
        3AM
        78°
        4AM
        77°
        5AM
        76°
        6AM
        76°
        6:35AM
        Sunrise
        7AM
        76°
        Precipitation
        8%
        Pollen
        Ragweed Pollen
        High
        Air Quality
        58
        Moderate
        UV Index
        0
        Low
        Additional Conditions
        1. Pressure 29.95 in
        2. Visibility 10 miles
        3. Clouds Clear
        4. Dew Point71°F
        5. Humidity 81%
        6. Rainfall 0 in
        7. Snow Depth 0 in
         KSUS Station History
        Almanac for September 4, 2026
        1. Forecast Average Record
        2. Temperature
        3. High 100°F 84°F 98°F 2011
        4. Low 76°F 61°F 31°F 1995
        5. Rain/Snow Depth
        6. Precipitation 0 in 3.6 in -
        7. Snow 0 in 0 in -
        Almanac for September 5, 2026
        1. Forecast Average Record
        2. Temperature
        3. High 100°F 84°F 98°F
        4. Low 76°F 61°F 46°F
        Astronomy
        1. Sun Rise Set
        2. Actual Time 6:34 AM 7:28 PM
        3. Civil Twilight 6:07 AM 7:55 PM
        4. Nautical Twilight 5:35 AM 8:27PM
        5. Astronomical Twilight 5:02 AM 9:00 PM
        1. Length of Visible Light 13h 47m
        2. Length of Day 12h 53m
        3. Tomorrow will be 2 minutes 27 seconds shorter
        1. Moon 11:59 PM 2:57 PM
        2. Last Quarter40% of the Moon is Illuminated
        Sep 4
        Waning Half Last Qtr
        Sep 10
        New Moon
        Sep 18
        Waxing Half First Qtr
        Sep 26
        Full Moon
        Precipitation
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