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O'Fallon, MO

84°F
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O'Fallon

Missouri

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O'Fallon, MO Weather
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May 17 - May 31

Sun 5/17

88° /73°
2%
Breezy this morning; otherwise, partly sunny and very warm; possible danger of dehydration and heatstroke while doing strenuous activities

RealFeel®95°

RealFeel Shade™86°

Max UV Index9.0 (Very High)

WindS 13 mph

Mon 5/18

81° /70°
87%
Humid with intervals of clouds and sunshine; breezy in the morning, then a couple of thunderstorms in the afternoon

RealFeel®86°

RealFeel Shade™83°

Max UV Index6.0 (High)

WindS 13 mph

Hours of Precipitation2

Hours of Rain2

Tue 5/19

79° /54°
88%
Cloudy and humid with a shower and t-storm; breezy in the morning, then not as warm in the afternoon; thunderstorms can bring localized damaging wind gusts

RealFeel®82°

RealFeel Shade™79°

Max UV Index3.0 (Moderate)

WindWSW 12 mph

Hours of Precipitation4

Hours of Rain4

Wed 5/20

67° /50°
12%
Cooler and less humid with sun and areas of high clouds

RealFeel®71°

RealFeel Shade™64°

Max UV Index8.0 (Very High)

WindNNE 9 mph

Thu 5/21

72° /59°
25%
Pleasant with times of clouds and sun

RealFeel®77°

RealFeel Shade™69°

Max UV Index6.0 (High)

WindENE 7 mph

Fri 5/22

74° /59°
87%
Cloudy with showers in the afternoon

RealFeel®72°

RealFeel Shade™72°

Max UV Index3.0 (Moderate)

WindENE 5 mph

Hours of Precipitation3.5

Hours of Rain3.5

Sat 5/23

75° /60°
30%
Cloudy with a couple of showers possible

RealFeel®78°

RealFeel Shade™73°

Max UV Index4.0 (Moderate)

WindNW 5 mph

Sun 5/24

79° /62°
30%
Mostly cloudy and humid with a thunderstorm possible

RealFeel®89°

RealFeel Shade™79°

Max UV Index8.0 (Very High)

WindENE 4 mph

Mon 5/25

80° /62°
35%
Mostly cloudy and humid with a couple of showers and thunderstorms possible

RealFeel®87°

RealFeel Shade™81°

Max UV Index4.0 (Moderate)

WindE 5 mph

Tue 5/26

81° /63°
61%
Clouds and breaks of sun; humid with a couple of thunderstorms, especially early in the day

RealFeel®91°

RealFeel Shade™84°

Max UV Index7.0 (High)

WindSE 4 mph

Hours of Precipitation2.5

Hours of Rain2.5

Wed 5/27

78° /60°
75%
Humid with rain

RealFeel®85°

RealFeel Shade™82°

Max UV Index3.0 (Moderate)

WindS 8 mph

Hours of Precipitation5

Hours of Rain5

Thu 5/28

78° /62°
49%
A shower in spots in the morning; otherwise, mainly cloudy and humid

RealFeel®89°

RealFeel Shade™85°

Max UV Index8.0 (Very High)

WindNNW 6 mph

Hours of Precipitation1

Hours of Rain1

Fri 5/29

80° /61°
60%
Humid with occasional rain

RealFeel®82°

RealFeel Shade™79°

Max UV Index2.0 (Low)

WindSE 7 mph

Hours of Precipitation3.5

Hours of Rain3.5

Sat 5/30

78° /58°
20%
Mostly sunny and less humid

RealFeel®86°

RealFeel Shade™76°

Max UV Index11.0 (Extreme)

WindWSW 6 mph

Sun 5/31

83° /64°
20%
Partly sunny and humid

RealFeel®94°

RealFeel Shade™88°

Max UV Index11.0 (Extreme)

WindWSW 6 mph

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World North America United States Missouri O'Fallon

Weather Near O'Fallon:

  • St. Charles, MO
  • St. Louis, MO
  • St. Peters, MO
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