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August weather forecast in O'Fallon

30 days Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

30 days Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Sun

Sunday

Mon

Monday

Tue

Tuesday

Wed

Wednesday

Thu

Thursday

Fri

Friday

Sat

Saturday

27 July, sun

	747 mmHg		72%
	3.6 m/s

27 July, Sunday. day, 30°; night, 22°; rain

28 July, mon

	747 mmHg		73%
	3.4 m/s

28 July, Monday. day, 31°; night, 22°; partly cloudy

29 July, tue

	747 mmHg		72%
	3.5 m/s

29 July, Tuesday. day, 30°; night, 22°; rain

30 July, wed

	748 mmHg		74%
	3.2 m/s

30 July, Wednesday. day, 29°; night, 21°; rain

31 July, thu

	748 mmHg		73%
	3 m/s

31 July, Thursday. day, 30°; night, 21°; clear

1 August, fri

	748 mmHg		72%
	3 m/s

1 August, Friday. day, 30°; night, 21°; clear

2 August, sat

	748 mmHg		71%
	3.3 m/s

2 August, Saturday. day, 31°; night, 22°; clear

3 August, sun

	747 mmHg		74%
	3.3 m/s

3 August, Sunday. day, 31°; night, 22°; rain

4 August, mon

	747 mmHg		72%
	3.4 m/s

4 August, Monday. day, 31°; night, 22°; partly cloudy

5 August, tue

	748 mmHg		73%
	3.5 m/s

5 August, Tuesday. day, 30°; night, 22°; rain

6 August, wed

	747 mmHg		72%
	3.5 m/s

6 August, Wednesday. day, 30°; night, 21°; partly cloudy

7 August, thu

	747 mmHg		72%
	3.5 m/s

7 August, Thursday. day, 30°; night, 21°; partly cloudy

8 August, fri

	747 mmHg		73%
	3.4 m/s

8 August, Friday. day, 30°; night, 22°; overcast

9 August, sat

	747 mmHg		74%
	3.4 m/s

9 August, Saturday. day, 30°; night, 21°; clear

10 August, sun

	747 mmHg		72%
	3.3 m/s

10 August, Sunday. day, 30°; night, 21°; clear

11 August, mon

	747 mmHg		71%
	3.3 m/s

11 August, Monday. day, 30°; night, 21°; clear

12 August, tue

	747 mmHg		70%
	3.5 m/s

12 August, Tuesday. day, 29°; night, 21°; partly cloudy

13 August, wed

	747 mmHg		74%
	3.4 m/s

13 August, Wednesday. day, 29°; night, 20°; rain

14 August, thu

	748 mmHg		73%
	3.4 m/s

14 August, Thursday. day, 28°; night, 20°; overcast

15 August, fri

	748 mmHg		74%
	3.3 m/s

15 August, Friday. day, 29°; night, 20°; partly cloudy

16 August, sat

	748 mmHg		72%
	3.5 m/s

16 August, Saturday. day, 29°; night, 21°; rain

17 August, sun

	748 mmHg		72%
	3.7 m/s

17 August, Sunday. day, 29°; night, 21°; rain

18 August, mon

	747 mmHg		73%
	3.6 m/s

18 August, Monday. day, 30°; night, 21°; clear

19 August, tue

	747 mmHg		74%
	3.6 m/s

19 August, Tuesday. day, 29°; night, 21°; partly cloudy

20 August, wed

	747 mmHg		75%
	3.9 m/s

20 August, Wednesday. day, 29°; night, 20°; rain

21 August, thu

	748 mmHg		74%
	3.6 m/s

21 August, Thursday. day, 29°; night, 20°; clear

22 August, fri

	749 mmHg		71%
	3.5 m/s

22 August, Friday. day, 30°; night, 20°; clear

23 August, sat

	748 mmHg		71%
	3.5 m/s

23 August, Saturday. day, 30°; night, 20°; clear

24 August, sun

	748 mmHg		71%
	3.9 m/s

24 August, Sunday. day, 30°; night, 21°; clear

25 August, mon

	748 mmHg		70%
	3.8 m/s

25 August, Monday. day, 30°; night, 21°; clear

26 August, tue

	748 mmHg		75%
	3.3 m/s

26 August, Tuesday. day, 30°; night, 21°; rain

27 August, wed

	747 mmHg		74%
	3.3 m/s

27 August, Wednesday. day, 30°; night, 21°; rain

28 August, thu

	747 mmHg		73%
	3.4 m/s

28 August, Thursday. day, 30°; night, 21°; clear

29 August, fri

	747 mmHg		73%
	3.4 m/s

29 August, Friday. day, 30°; night, 21°; clear

30 August, sat

	748 mmHg		73%
	3.3 m/s

30 August, Saturday. day, 29°; night, 20°; clear

31 August, sun

	748 mmHg		74%
	3.3 m/s

31 August, Sunday. day, 29°; night, 20°; rain

1 September, mon

	748 mmHg		74%
	3.6 m/s

1 September, Monday. day, 28°; night, 20°; partly cloudy

2 September, tue

	748 mmHg		72%
	3.3 m/s

2 September, Tuesday. day, 28°; night, 19°; partly cloudy

3 September, wed

	748 mmHg		71%
	3.3 m/s

3 September, Wednesday. day, 29°; night, 19°; clear

4 September, thu

	748 mmHg		71%
	3.6 m/s

4 September, Thursday. day, 29°; night, 19°; clear

5 September, fri

	749 mmHg		71%
	3.8 m/s

5 September, Friday. day, 28°; night, 18°; clear

6 September, sat

	748 mmHg		70%
	3.9 m/s

6 September, Saturday. day, 28°; night, 19°; clear

Average data for 10 years

O'Fallon August

14

sunny days

9

days with precipitation

4

cloudy days

14 sunny days; 9 days with precipitation; 4 cloudy days;

73

%

air humidity

2.3

m/s

WindS

81

mm of precipitation

(8% of annual average)

air humidity 73%; 81 millimeters of precipitation (8% of annual average); Wind southerly 2.3 Meters per second

Weather graphs for August

TemperaturePrecipitation chance, %Humidity, %Wind, m/sPressure, mmHg

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SE

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SE

SE

1

Average data for 10 years

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Daytime temperature

Night-time temperature

Cities near you

Kansas City
St. Louis
Dixon
Ottawa
Iowa City
Washington
Memphis
Paris
Lake Ozark

Cities with similar weather in August

Kemer
Rome
Athens
Jerba
Madrid
Taraz
Gudauta
Washington
Bar

The weather forecast for August 2025 is based on historical data from the past 10 years.

In August, the weather in O'Fallon is typically hot. Average daily high temperature in August is about 30 degrees above zero. On average, O'Fallon has 14 sunny, 9 rainy, 6 partly cloudy, and 2 cloudy days in August. The rains are usually heavy.

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