Go Back
  • For Business
  • |
  • Warnings
  • Data Suite
  • Forensics
  • Advertising
  • Superior Accuracy™
Hurricane Erin to fuel dangerous surf, coastal flood risk from Carolinas to New England. Chevron right
Puerto Rico, Leeward Islands brace for Hurricane Erin. Get the details. Chevron right

O'Fallon, MO

76°F
Location Chevron down
Location News Videos
Use Current Location
Recent

O'Fallon

Missouri

76°
No results found.
Try searching for a city, zip code or point of interest.
settings
O'Fallon, MO Weather
Today WinterCast Local {stormName} Tracker Hourly Daily Radar MinuteCast® Monthly Air Quality Health & Activities

Around the Globe

Hurricane Tracker

Severe Weather

Radar & Maps
News

News & Features

Astronomy

Business

Climate

Health

Recreation

Sports

Travel
For Business

Warnings

Data Suite

Forensics

Advertising

Superior Accuracy™

Video

Winter Center
Today Hourly

Daily

 Radar MinuteCast® Monthly Air Quality Health & Activities
Heat Advisory

August 16 - September 29

Sat 8/16

97° /72°
55%
Hot with sun and some clouds; a thunderstorm on the prowl this afternoon; thunderstorms can bring localized damaging wind gusts
alerts

Heat Advisory

12:00 PM Friday - 8:00 PM Monday

RealFeel®110°

RealFeel Shade™102°

Max UV Index9.0 (Very High)

WindS 6 mph

Sun 8/17

97° /72°
21%
Mostly sunny and very hot; danger of dehydration and heatstroke if outside for extended periods of time
alerts

Heat Advisory

12:00 PM Friday - 8:00 PM Monday

RealFeel®109°

RealFeel Shade™102°

Max UV Index9.0 (Very High)

WindN 6 mph

Mon 8/18

101° /74°
7%
Mostly sunny and very hot; danger of dehydration and heatstroke if outside for extended periods of time
alerts

Heat Advisory

12:00 PM Friday - 8:00 PM Monday

RealFeel®110°

RealFeel Shade™103°

Max UV Index9.0 (Very High)

WindS 6 mph

Tue 8/19

94° /72°
55%
Hot with more clouds than sun; a thunderstorm in spots in the afternoon; danger of dehydration and heatstroke if outside for extended periods of time

RealFeel®104°

RealFeel Shade™99°

Max UV Index5.0 (Moderate)

WindNNW 6 mph

Wed 8/20

84° /65°
89%
Strong thunderstorms in the morning; rather cloudy and not as hot with a strong t-storm in spots in the afternoon

RealFeel®93°

RealFeel Shade™87°

Max UV Index5.0 (Moderate)

WindNNE 6 mph

Thu 8/21

82° /64°
80%
Partly sunny; watch for a strong thunderstorm in the morning followed by a thunderstorm in parts of the area in the afternoon

RealFeel®88°

RealFeel Shade™81°

Max UV Index8.0 (Very High)

WindENE 8 mph

Fri 8/22

86° /66°
55%
Partly sunny with a thunderstorm in parts of the area

RealFeel®90°

RealFeel Shade™85°

Max UV Index7.0 (High)

WindNE 5 mph

Sat 8/23

90° /65°
3%
Partly sunny

RealFeel®94°

RealFeel Shade™88°

Max UV Index7.0 (High)

WindN 4 mph

Sun 8/24

86° /64°
65%
Variable cloudiness with a thunderstorm or two in the afternoon

RealFeel®93°

RealFeel Shade™85°

Max UV Index8.0 (Very High)

WindN 2 mph

Mon 8/25

86° /68°
20%
Clouds giving way to some sun

RealFeel®90°

RealFeel Shade™84°

Max UV Index5.0 (Moderate)

WindNE 5 mph

Tue 8/26

89° /68°
14%
Sun through high clouds

RealFeel®95°

RealFeel Shade™94°

Max UV Index4.0 (Moderate)

WindE 6 mph

Wed 8/27

91° /70°
55%
Considerable cloudiness, hot and humid; occasional rain in the afternoon

RealFeel®94°

RealFeel Shade™91°

Max UV Index5.0 (Moderate)

WindSE 7 mph

Thu 8/28

90° /70°
10%
Hot with sunshine and a few clouds

RealFeel®95°

RealFeel Shade™90°

Max UV Index8.0 (Very High)

WindS 8 mph

Fri 8/29

85° /63°
25%
Considerable cloudiness

RealFeel®88°

RealFeel Shade™88°

Max UV Index2.0 (Low)

WindENE 5 mph

Sat 8/30

87° /67°
10%
Mostly sunny and humid

RealFeel®97°

RealFeel Shade™90°

Max UV Index7.0 (High)

WindENE 4 mph

Sun 8/31

88° /68°
10%
Mostly sunny and humid

RealFeel®98°

RealFeel Shade™91°

Max UV Index7.0 (High)

WindSW 1 mph

Mon 9/1

88° /68°
5%
Very warm and humid with sunshine

RealFeel®98°

RealFeel Shade™92°

Max UV Index7.0 (High)

WindESE 2 mph

Tue 9/2

87° /67°
65%
A couple of showers and a thunderstorm in the morning; otherwise, humid with times of clouds and sun

RealFeel®96°

RealFeel Shade™94°

Max UV Index3.0 (Moderate)

WindNE 4 mph

Wed 9/3

87° /67°
65%
Partly sunny and humid; a couple of afternoon showers and a thunderstorm

RealFeel®98°

RealFeel Shade™92°

Max UV Index7.0 (High)

WindSSW 4 mph

Thu 9/4

85° /66°
40%
Humid with increasing cloudiness; a thunderstorm in spots in the afternoon

RealFeel®93°

RealFeel Shade™93°

Max UV Index4.0 (Moderate)

WindWNW 2 mph

Fri 9/5

86° /66°
55%
A morning thundershower; otherwise, humid with partial sunshine

RealFeel®94°

RealFeel Shade™88°

Max UV Index7.0 (High)

WindNE 5 mph

Sat 9/6

85° /65°
10%
Mostly sunny and humid

RealFeel®95°

RealFeel Shade™88°

Max UV Index7.0 (High)

WindSSE 2 mph

Sun 9/7

85° /66°
65%
Humid with more clouds than sun; a couple of afternoon showers and a thunderstorm

RealFeel®91°

RealFeel Shade™91°

Max UV Index3.0 (Moderate)

WindS 5 mph

Mon 9/8

86° /65°
20%
Humid with partial sunshine

RealFeel®87°

RealFeel Shade™84°

Max UV Index5.0 (Moderate)

WindNNW 9 mph

Tue 9/9

82° /64°
25%
Sun giving way to increasing clouds

RealFeel®82°

RealFeel Shade™82°

Max UV Index5.0 (Moderate)

WindNNW 2 mph

Wed 9/10

83° /63°
20%
Partly sunny and humid

RealFeel®91°

RealFeel Shade™84°

Max UV Index6.0 (High)

WindWSW 2 mph

Thu 9/11

84° /64°
20%
Mostly sunny and humid

RealFeel®89°

RealFeel Shade™86°

Max UV Index6.0 (High)

WindENE 2 mph

Fri 9/12

84° /59°
0%
Plenty of sunshine

RealFeel®87°

RealFeel Shade™83°

Max UV Index6.0 (High)

WindSE 4 mph

Sat 9/13

84° /60°
0%
Plenty of sunshine

RealFeel®87°

RealFeel Shade™84°

Max UV Index6.0 (High)

WindSSE 6 mph

Sun 9/14

83° /60°
1%
Brilliant sunshine

RealFeel®86°

RealFeel Shade™83°

Max UV Index6.0 (High)

WindSSE 6 mph

Mon 9/15

74° /51°
0%
Partly sunny and not as warm with lower humidity

RealFeel®74°

RealFeel Shade™71°

Max UV Index6.0 (High)

WindN 12 mph

Tue 9/16

73° /53°
0%
Partly sunny

RealFeel®74°

RealFeel Shade™71°

Max UV Index6.0 (High)

WindENE 6 mph

Wed 9/17

74° /56°
3%
Periods of clouds and sunshine

RealFeel®74°

RealFeel Shade™71°

Max UV Index6.0 (High)

WindESE 8 mph

Thu 9/18

73° /55°
59%
Occasional rain

RealFeel®74°

RealFeel Shade™74°

Max UV Index1.0 (Low)

WindSE 5 mph

Fri 9/19

78° /59°
56%
Intervals of clouds and sunshine; a thundershower in spots in the morning followed by a couple of showers in the afternoon

RealFeel®78°

RealFeel Shade™74°

Max UV Index5.0 (Moderate)

WindWNW 7 mph

Sat 9/20

75° /59°
1%
Mostly sunny

RealFeel®78°

RealFeel Shade™74°

Max UV Index5.0 (Moderate)

WindE 5 mph

Sun 9/21

84° /60°
40%
Times of clouds and sun with a thunderstorm in parts of the area

RealFeel®91°

RealFeel Shade™89°

Max UV Index5.0 (Moderate)

WindSW 5 mph

Mon 9/22

85° /59°
25%
Clouds yielding to sun

RealFeel®91°

RealFeel Shade™88°

Max UV Index5.0 (Moderate)

WindE 4 mph

Tue 9/23

80° /59°
25%
Clouds and sunshine

RealFeel®82°

RealFeel Shade™80°

Max UV Index5.0 (Moderate)

WindE 9 mph

Wed 9/24

82° /58°
25%
Humid with clouds and sun

RealFeel®84°

RealFeel Shade™82°

Max UV Index4.0 (Moderate)

WindS 9 mph

Thu 9/25

76° /46°
1%
Clouds giving way to some sun

RealFeel®77°

RealFeel Shade™74°

Max UV Index5.0 (Moderate)

WindNNE 8 mph

Fri 9/26

72° /58°
0%
Mostly sunny

RealFeel®75°

RealFeel Shade™72°

Max UV Index5.0 (Moderate)

WindESE 4 mph

Sat 9/27

79° /57°
1%
Plenty of sun

RealFeel®79°

RealFeel Shade™77°

Max UV Index5.0 (Moderate)

WindS 7 mph

Sun 9/28

78° /59°
2%
Sunshine and a few clouds

RealFeel®78°

RealFeel Shade™75°

Max UV Index5.0 (Moderate)

WindNNW 7 mph

Mon 9/29

70° /48°
0%
Sunshine and some clouds

RealFeel®70°

RealFeel Shade™67°

Max UV Index5.0 (Moderate)

WindNE 8 mph

Around the Globe

Hurricane Tracker

Severe Weather

Radar & Maps

News

Video

Winter Center

Top Stories

Hurricane

Erin intensifies into hurricane as it tracks near Puerto Rico

8 hours ago

Recreation

Man rescued after falling 30 feet down waterfall in Maine

19 hours ago

Severe Weather

Severe storms, flash flooding to pester north-central US

8 hours ago

Weather News

New York skyscraper had 1-in-16 chance of collapse. Only one man knew

21 hours ago

Hurricane

Hurricane safety: Explaining rapid intensification and how to prepare

19 hours ago

 More Stories

Featured Stories

Weather News

Heavy rain in Indian Kashmir leaves dozens dead, more than 200 missing

22 hours ago

Weather News

Pompeii’s remains reveal a hidden postscript

21 hours ago

Astronomy

Goodbye long days: Where sunset is now happening before 8 pm

19 hours ago

Weather News

US teen pilot accused of unauthorized Antarctic landing reaches deal

1 day ago

Weather News

New York skyscraper had 1-in-16 chance of collapse. Only one man knew

21 hours ago
World North America United States Missouri O'Fallon

Weather Near O'Fallon:

  • St. Charles, MO
  • St. Louis, MO
  • St. Peters, MO
Company
Proven Superior Accuracy™ About AccuWeather Digital Advertising Careers Press Contact Us
Products & Services
For Business For Partners For Advertising AccuWeather APIs AccuWeather Connect RealFeel® and RealFeel Shade™ Personal Weather Stations
Apps & Downloads
iPhone App Android App See all Apps & Downloads
Subscription Services
AccuWeather Premium AccuWeather Professional
More
AccuWeather Ready Business Health Hurricane Leisure and Recreation Severe Weather Space and Astronomy Sports Travel Weather News Winter Center
Company
Proven Superior Accuracy™ About AccuWeather Digital Advertising Careers Press Contact Us
Products & Services
For Business For Partners For Advertising AccuWeather APIs AccuWeather Connect RealFeel® and RealFeel Shade™ Personal Weather Stations
Apps & Downloads
iPhone App Android App See all Apps & Downloads
Subscription Services
AccuWeather Premium AccuWeather Professional
More
AccuWeather Ready Business Health Hurricane Leisure and Recreation Severe Weather Space and Astronomy Sports Travel Weather News Winter Center
© 2025 AccuWeather, Inc. "AccuWeather" and sun design are registered trademarks of AccuWeather, Inc. All Rights Reserved.
Terms of Use | Privacy Policy | Cookie Policy | About Your Privacy Do Not Sell or Share My Personal Information

...

...

...