Climate and monthly weather forecast
Vandalia, IL

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Weather in January

January, like December, in Vandalia, Illinois, is an icy winter month, with an average temperature ranging between max 36°F (2.2°C) and min 23.4°F (-4.8°C). January, with average temperatures reaching a high of 36°F (2.2°C) and a low of 23.4°F (-4.8°C), is the coldest month. Weather in January »

Weather in February

February, the last month of the winter in Vandalia, is also a wintry month, with an average temperature fluctuating between 40.6°F (4.8°C) and 27°F (-2.8°C). February brings an average high-temperature of a still wintry 40.6°F (4.8°C), showing a slight difference from January's 36°F (2.2°C). Weather in February »

Weather in March

The first month of the spring, March, is a cool month in Vandalia, Illinois, with an average temperature ranging between max 53.1°F (11.7°C) and min 36.9°F (2.7°C). March's arrival brings a temperature shift, moving from an icy 40.6°F (4.8°C) in February to a fresh 53.1°F (11.7°C). Weather in March »

Weather in April

April in Vandalia, Illinois, is a comfortable spring month, with temperature in the range of an average high of 63.7°F (17.6°C) and an average low of 46.6°F (8.1°C). April sees a rise in the average high-temperature, climbing from a cool 53.1°F (11.7°C) in March to a comfortable 63.7°F (17.6°C). Weather in April »

Weather in May

The last month of the spring, May, is a warm month in Vandalia, Illinois, with an average temperature ranging between max 73.6°F (23.1°C) and min 56.8°F (13.8°C). The shift into May is characterized by a rise in the average high-temperature, transitioning from April's comfortable 63.7°F (17.6°C) to a warm 73.6°F (23.1°C). Weather in May »

Weather in June

The first month of the summer, June, is still a warm month in Vandalia, Illinois, with an average temperature fluctuating between 82.4°F (28°C) and 65.7°F (18.7°C). As Vandalia welcomes June, the average high-temperature sees a modest rise, transitioning from 73.6°F (23.1°C) in May to a still warm 82.4°F (28°C). Weather in June »

Weather in July

July, the same as June, is a moderately hot summer month in Vandalia, Illinois, with temperature in the range of an average low of 67.3°F (19.6°C) and an average high of 84°F (28.9°C). July temperatures tend to peak at an average high of 84°F (28.9°C) and dip to a low of 67.3°F (19.6°C). July's average heat index is appraised at a very hot 95°F (35°C). Weather in July »

Weather in August

August, the last month of the summer in Vandalia, is another warm month, with an average temperature fluctuating between 82.6°F (28.1°C) and 65.1°F (18.4°C). The arrival of August is marked by an average high-temperature of a still moderately hot 82.6°F (28.1°C), bearing a close resemblance to July. Weather in August »

Weather in September

The first month of the autumn, September, is still a warm month in Vandalia, Illinois, with an average temperature ranging between min 59.4°F (15.2°C) and max 77.9°F (25.5°C). September's onset brings an average high-temperature of a still moderately hot 77.9°F (25.5°C), showing a minute difference from August's 82.6°F (28.1°C). Weather in September »

Weather in October

October, like September, in Vandalia, Illinois, is another refreshing autumn month, with an average temperature varying between 48.6°F (9.2°C) and 65.1°F (18.4°C). The onset of October comes with a shift in the average high-temperature, falling from a moderately hot 77.9°F (25.5°C) in September to a refreshing 65.1°F (18.4°C). Weather in October »

Weather in November

The last month of the autumn, November, is also a fresh month in Vandalia, Illinois, with an average temperature varying between 51.8°F (11°C) and 37.2°F (2.9°C). The transition into November indicates a reduction in the average high-temperature, down to a fresh 51.8°F (11°C) from October's enjoyable 65.1°F (18.4°C). Weather in November »

Weather in December

December, the first month of the winter in Vandalia, is also a wintry month, with temperature in the range of an average high of 41°F (5°C) and an average low of 29.5°F (-1.4°C). Stepping into December, Vandalia observes a temperature decline, with the average high falling from November's cool 51.8°F (11°C) to a cold 41°F (5°C). Weather in December »

Frequently asked questions

What time of the year is the coldest?

January is the month when Vandalia experiences its coldest temperatures, averaging a high of 36°F (2.2°C) and a low of 23.4°F (-4.8°C).

How much does it rain?

In Vandalia, Illinois, during the entire year, the rain falls for 164.1 days and collects up to 36.73" (933mm) of precipitation.

When does it snow?

Months with snowfall are January through April, November and December.

How much does it snow?

In Vandalia, Illinois, during the entire year, snow falls for 25.1 days and aggregates up to 8.19" (208mm) of snow.

What is the month with the least sunshine?

With an average of 4.3h of sunshine, January has the least sunshine of the year.

When is the lowest UV index?

The months with the lowest UV index are January, February, November and December, with an average maximum UV index of 2.

What is the driest month?

February is the month with the least rainfall. Rain falls for 9.6 days and accumulates 2.01" (51mm) of precipitation.

When is Daylight Saving Time (DST)?

On Sunday, March 10. 2024, at 2:00 am, Daylight Saving Time starts, and the time zone changes from CST to CDT. Daylight Saving Time ends Sunday, November 3. 2024, at 2:00 am, and the time zone reverts from CDT to CST.

When it does not snow?

May through October are months without snowfall.

What is the wettest month?

The month with the most rainfall in Vandalia is June, when the rain falls for 17.2 days and typically aggregates up to 4.57" (116mm) of precipitation.

When are the longest days?

June has the longest days of the year, with an average of 14h and 54min of daylight.

What month has the most sunshine?

The month with the most sunshine is June, with an average of 10.3h of sunshine.

When is the highest UV index?

The months with the highest UV index are June through August, with an average maximum UV index of 6.

What are the warmest months?

July is the month when Vandalia sees the average highest temperatures, with a high of 84°F (28.9°C) and a low of 67.3°F (19.6°C).

What is the most humid month?

The most humid month is July, with an average relative humidity of 81%.

What is the least humid month?

With an average relative humidity of 71%, October is the least humid month.

When does it snow the most in Vandalia?

The month with the most snowfall is December, when snow falls for 5.1 days and typically aggregates up to 2.4" (61mm) of snow.

What is the month with the shortest days in Vandalia?

With an average of 9h and 30min of daylight, December has the shortest days of the year.

Average temperature
Vandalia, IL

Average temperature - Vandalia, IL

The warmest month (with the highest average high temperature) is July (84°F).
The month with the lowest average high temperature is January (36°F).

The month with the highest average low temperature is July (67.3°F).
The coldest month (with the lowest average low temperature) is January (23.4°F).

Average pressure
Vandalia, IL

Average pressure - Vandalia, IL

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

Average wind speed
Vandalia, IL

Average wind speed - Vandalia, IL

The windiest month (with the highest average wind speed) is January (10.3mph).
The calmest months (with the lowest average wind speed) are July and August (6mph).

Average humidity
Vandalia, IL

Average humidity - Vandalia, IL

The month with the highest relative humidity is July (81%).
The month with the lowest relative humidity is October (71%).

Average rainfall
Vandalia, IL

Average rainfall - Vandalia, IL

The wettest month (with the highest rainfall) is June (4.57").
The driest month (with the least rainfall) is February (2.01").

Average rainfall days
Vandalia, IL

Average rainfall days - Vandalia, IL

The month with the highest number of rainy days is May (18.3 days).
The month with the least rainy days is January (9.2 days).

Average snowfall
Vandalia, IL

Average snowfall - Vandalia, IL

The month with the highest snowfall is December (2.4").
The months with the least snowfall are May, June, July, August, September and October (0").

Average snowfall days
Vandalia, IL

Average snowfall days - Vandalia, IL

The month with the highest number of snowfall days is January (8.3 days).
The months with the least snowfall days are May, June, July, August and September (0 days).

Average daylight / Average sunshine
Vandalia, IL

Average daylight / Average sunshine - Vandalia, IL

The month with the longest days is June (Average daylight: 14h and 54min).
The month with the shortest days is December (Average daylight: 9h and 30min).

The month with the most sunshine is June (Average sunshine: 10h and 18min).
The month with the least sunshine is January (Average sunshine: 4h and 18min).

Average sunshine days
Vandalia, IL

Average sunshine days - Vandalia, IL

The month with the most sunshine days is October (17.2 days).
The month with the least sunshine days is July (8.6 days).

Average UV index
Vandalia, IL

Average UV index - Vandalia, IL

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

Average visibility
Vandalia, IL

Average visibility - Vandalia, IL

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).

Vandalia, Illinois, USA

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