April weather forecast
O'Fallon, IL

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Weather in April

April in O'Fallon, Illinois, is a refreshing spring month, with temperature in the range of an average low of 47.8°F (8.8°C) and an average high of 64.9°F (18.3°C).

Temperature

As April sets, the average high-temperature shows an increase, moving up from a cool 54.5°F (12.5°C) in March to a comfortable 64.9°F (18.3°C). In April, O'Fallon encounters an average low-temperature of 47.8°F (8.8°C) during the night.

Humidity

The average relative humidity in April in O'Fallon is 77%.

Rainfall

In O'Fallon, in April, during 12.3 rainfall days, 1.1" (28mm) of precipitation is typically accumulated. In O'Fallon, during the entire year, the rain falls for 108.8 days and collects up to 10.24" (260mm) of precipitation.

Snowfall

In O'Fallon, snow does not fall in April through October.

Daylight

In April, the average length of the day is 13h and 14min.
On the first day of April in O'Fallon, sunrise is at 6:43 am and sunset at 7:23 pm. On the last day of the month, sunrise is at 6:02 am and sunset at 7:51 pm CDT.

Sunshine

The average sunshine in April is 8.6h.

UV index

In April, the average daily maximum UV index is 4. A UV Index value of 3 to 5 symbolizes a moderate health risk from unprotected exposure to Sun's UV rays for the ordinary person.
Note: In April, the UV index of 4 transforms into the following advice:
Adopt protective measures - Requirement to safeguard skin and eyes from harm exists. Direct Sun exposure should be minimized especially during midday when radiation is most intense. Always opt for UVA and UVB-resistant sunglasses on radiant days. Caution! The reflection of snow can nearly double the intensity of the Sun's UV radiation.
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Frequently asked questions

What are the temperatures in O'Fallon in April?

An average high-temperature, in April, in O'Fallon, is 64.9°F (18.3°C) and the average low-temperature is 47.8°F (8.8°C).

What is the average humidity in April in O'Fallon?

The average relative humidity in April in O'Fallon is 77%.

How many days does it rain in April in O'Fallon?

In O'Fallon, Illinois, during April, the rain falls for 12.3 days and regularly aggregates up to 1.1" (28mm) of precipitation.

When it does not snow in O'Fallon?

April through October are months without snowfall in O'Fallon, Illinois.

Does it snow in O'Fallon in April?

In April, in O'Fallon, it doesn't snow. March is the latest month when it typically snows.

What is the average length of the day in April in O'Fallon?

In April, the average day length in O'Fallon is 13h and 14min.

When is the sunrise / sunset in April in O'Fallon?

On the first day of April, sunrise is at 6:43 am and sunset at 7:23 pm. On the last day of the month, sunrise is at 6:02 am and sunset at 7:51 pm CDT.

How long on average sun shines in April in O'Fallon?

The average sunshine duration in April in O'Fallon is 8.6h.

What is the UV index reading in April in O'Fallon?

In O'Fallon, Illinois, the average daily maximum UV index in April is 4. A UV Index value of 3 to 5 symbolizes a medium health risk from exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average snowfall
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in April
O'Fallon, IL

Average temperature in April - O
  • Average high temperature in April: 64.9°F

The warmest month (with the highest average high temperature) is July (85.6°F).
The month with the lowest average high temperature is January (37.8°F).

  • Average low temperature in April: 47.8°F

The month with the highest average low temperature is July (68.2°F).
The coldest month (with the lowest average low temperature) is January (24.6°F).

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Average pressure in April
O'Fallon, IL

Average pressure in April - O
  • Average pressure in April: 29.94"Hg

The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).

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Average wind speed in April
O'Fallon, IL

Average wind speed in April - O
  • Average wind speed in April: 9.1mph

The windiest month (with the highest average wind speed) is January (9.5mph).
The calmest month (with the lowest average wind speed) is July (5.6mph).

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Average humidity in April
O'Fallon, IL

Average humidity in April - O
  • Average humidity in April: 77%

The months with the highest relative humidity are May, July and August (79%).
The month with the lowest relative humidity is October (70%).

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Average rainfall in April
O'Fallon, IL

Average rainfall in April - O
  • Average rainfall in April: 1.1"

The wettest month (with the highest rainfall) is July (1.42").
The driest month (with the least rainfall) is December (0.31").

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Average rainfall days in April
O'Fallon, IL

Average rainfall days in April - O
  • Average rainfall days in April: 12.3 days

The month with the highest number of rainy days is July (13.1 days).
The month with the least rainy days is December (4.6 days).

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Average snowfall in April
O'Fallon, IL

Average snowfall in April - O
  • Average snowfall in April: 0"

The month with the highest snowfall is January (0.51").
The months with the least snowfall are April, May, June, July, August, September and October (0").

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Average snowfall days in April
O'Fallon, IL

Average snowfall days in April - O
  • Average snowfall days in April: 0.1 days

The month with the highest number of snowfall days is January (4.7 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).

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Average daylight in April /
Average sunshine in April
O'Fallon, IL

Average daylight in April / Average sunshine in April - O
  • Average daylight in April: 13h and 1min

The month with the longest days is June (Average daylight: 14h and 48min).
The month with the shortest days is December (Average daylight: 9h and 30min).

  • Average sunshine in April: 8h and 4min

The months with the most sunshine are June and July (Average sunshine: 10h and 24min).
The month with the least sunshine is January (Average sunshine: 4h and 30min).

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Average sunshine days in April
O'Fallon, IL

Average sunshine days in April - O
  • Average sunshine days in April: 15.8 days

The month with the most sunshine days is December (23.6 days).
The months with the least sunshine days are May and July (15.5 days).

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Average UV index in April
O'Fallon, IL

Average UV index in April - O
  • Average UV index in April: 4

The months with the highest UV index are May, June, July and August (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 2).

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Average cloud cover in April
O'Fallon, IL

Average cloud cover in April - O
  • Average cloud cover in April: 42

The month with the most cloud cover is January (Cloud cover 51).
The month with the least cloud cover is August (Cloud cover 28).

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Average visibility in April
O'Fallon, IL

Average visibility in April - O
  • Average visibility in April: 6mi

The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).

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O'Fallon, Illinois, USA

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