Climate and monthly weather forecast
Petersburg, IL

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Weather in January

January, the same as December, is another cold winter month in Petersburg, Illinois, with an average temperature fluctuating between 32.9°F (0.5°C) and 20.7°F (-6.3°C). The month of January sees the lowest average temperatures, reaching 32.9°F (0.5°C) at the peak and 20.7°F (-6.3°C) at the low. Weather in January »

Weather in February

The last month of the winter, February, is another cold month in Petersburg, Illinois, with an average temperature ranging between min 24.4°F (-4.2°C) and max 37.9°F (3.3°C). Petersburg marks the arrival of February with an average high-temperature of a still wintry 37.9°F (3.3°C), hardly different from January's 32.9°F (0.5°C). Weather in February »

Weather in March

March, the first month of the spring in Petersburg, is a cool month, with an average temperature ranging between min 35.2°F (1.8°C) and max 50.9°F (10.5°C). With the onset of March, the average high-temperature slightly shifts from February's cold 37.9°F (3.3°C) to a cool 50.9°F (10.5°C). Weather in March »

Weather in April

April in Petersburg, Illinois, is an enjoyable spring month, with temperature in the range of an average low of 46°F (7.8°C) and an average high of 63°F (17.2°C). As Petersburg transitions into April, a rise in the average high-temperature is observed, moving from a fresh 50.9°F (10.5°C) in March to a refreshing 63°F (17.2°C). Weather in April »

Weather in May

May, the last month of the spring in Petersburg, is an agreeable month, with an average temperature varying between 55.9°F (13.3°C) and 72.9°F (22.7°C). Petersburg in May experiences an increase in the average high-temperature, moving from April's enjoyable 63°F (17.2°C) to a pleasant 72.9°F (22.7°C). Weather in May »

Weather in June

June, the first month of the summer in Petersburg, is a warm month, with an average temperature fluctuating between 64.2°F (17.9°C) and 81°F (27.2°C). As June arrives, a slight rise in the average high-temperature is observed, moving from an agreeable 72.9°F (22.7°C) in May to a moderately hot 81°F (27.2°C). Weather in June »

Weather in July

July, like June, in Petersburg, Illinois, is a moderately hot summer month, with an average temperature fluctuating between 66°F (18.9°C) and 82.8°F (28.2°C). Petersburg's temperatures peak on average in July, reaching 82.8°F (28.2°C) at their highest and 66°F (18.9°C) at their lowest. The heat index in July is computed to be a hot 91.4°F (33°C). Weather in July »

Weather in August

The last month of the summer, August, is another warm month in Petersburg, Illinois, with an average temperature ranging between max 82°F (27.8°C) and min 64°F (17.8°C). Petersburg observes a minor difference in average high-temperatures between July's 82.8°F (28.2°C) and August's 82°F (27.8°C). Weather in August »

Weather in September

September, the first month of the autumn in Petersburg, is still a warm month, with an average temperature fluctuating between 77.4°F (25.2°C) and 58.5°F (14.7°C). The arrival of September sees a recorded average high-temperature of a still moderately hot 77.4°F (25.2°C), showing little divergence from the previous month's conditions. Weather in September »

Weather in October

October, like September, in Petersburg, Illinois, is another refreshing autumn month, with an average temperature ranging between max 63.9°F (17.7°C) and min 47.7°F (8.7°C). The transition into October involves a decrease in the average high-temperature, falling from a moderately hot 77.4°F (25.2°C) in September to a refreshing 63.9°F (17.7°C). Weather in October »

Weather in November

The last month of the autumn, November, is also a fresh month in Petersburg, Illinois, with an average temperature fluctuating between 50°F (10°C) and 36°F (2.2°C). November suggests a modest reduction in the average high-temperature, shifting from an enjoyable 63.9°F (17.7°C) in October to a fresh 50°F (10°C). Weather in November »

Weather in December

The first month of the winter, December, is also an icy month in Petersburg, Illinois, with an average temperature ranging between max 38.5°F (3.6°C) and min 27.5°F (-2.5°C). With December's arrival, Petersburg, Illinois, sees a decrease in average high-temperatures, moving from a fresh 50°F (10°C) in November to a wintry 38.5°F (3.6°C). Weather in December »
Updated: Feb 12, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What month is the coldest in Petersburg?

January, known for its average high temperature of 32.9°F (0.5°C) and an average low temperature of 20.7°F (-6.3°C), is the coldest month.

How many days does it rain in Petersburg?

Throughout the year, in Petersburg, Illinois, there are 146.4 rainfall days, and 30.67" (779mm) of precipitation is accumulated.

When does it snow in Petersburg?

January through April, October through December are months with snowfall.

When does it snow the most in Petersburg?

January is the month with the most snowfall in Petersburg. Snow falls for 10.3 days and accumulates 4.02" (102mm) of snow.

How many days does it snow in Petersburg?

In Petersburg, during the entire year, snow falls for 29.2 days and aggregates up to 10.39" (264mm) of snow.

What is the month with the least sunshine in Petersburg?

January has the least sunshine of the year, with an average of 4.1h of sunshine.

What is the month with the lowest UV index in Petersburg?

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

When is Daylight Saving Time (DST) in Petersburg?

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.

What is the wettest month in Petersburg?

The month with the most rainfall is May, when the rain falls for 18.3 days and typically aggregates up to 3.82" (97mm) of precipitation.

When it does not snow in Petersburg?

In Petersburg, Illinois, snow does not fall in May through September.

When are the longest days in Petersburg?

The month with the longest days in Petersburg is June, with an average of 15h and 0min of daylight.

What month has the most sunshine in Petersburg?

June has the most sunshine of the year, with an average of 10.2h of sunshine.

What is the month with the highest UV index in Petersburg?

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

What are the warmest months in Petersburg?

With average high temperatures of 82.8°F (28.2°C) and lows of 66°F (18.9°C), July is the warmest month.

What is the most humid month in Petersburg?

The most humid month in Petersburg, Illinois, is July, with an average relative humidity of 84%.

What is the least humid month in Petersburg?

With an average relative humidity of 70%, October is the least humid month in Petersburg.

What is the driest month in Petersburg?

December is the month with the least rainfall in Petersburg, Illinois. Rain falls for 8.1 days and accumulates 1.5" (38mm) of precipitation.

What is the month with the shortest days in Petersburg?

The month with the shortest days in Petersburg, Illinois, is December, with an average of 9h and 24min of daylight.

Average pressure
Petersburg, IL

Average pressure - Petersburg, IL

The month with the highest atmospheric pressure is January (30.15"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).

Average wind speed
Petersburg, IL

Average wind speed - Petersburg, IL

The windiest months (with the highest average wind speed) are January, February and April (10.3mph).
The calmest months (with the lowest average wind speed) are July and August (6.3mph).

Average humidity
Petersburg, IL

Average humidity - Petersburg, IL

The month with the highest relative humidity is July (84%).
The month with the lowest relative humidity is October (70%).

Average rainfall
Petersburg, IL

Average rainfall - Petersburg, IL

The wettest month (with the highest rainfall) is May (3.82").
The driest month (with the least rainfall) is December (1.5").

Average rainfall days
Petersburg, IL

Average rainfall days - Petersburg, IL

The month with the highest number of rainy days is May (18.3 days).
The month with the least rainy days is February (6.2 days).

Average snowfall
Petersburg, IL

Average snowfall - Petersburg, IL

The month with the highest snowfall is January (4.02").
The months with the least snowfall are May, June, July, August and September (0").

Average snowfall days
Petersburg, IL

Average snowfall days - Petersburg, IL

The month with the highest number of snowfall days is January (10.3 days).
The months with the least snowfall days are May, June, July, August and September (0 days).

Average daylight / Average sunshine
Petersburg, IL

Average daylight / Average sunshine - Petersburg, IL

The month with the longest days is June (Average daylight: 15h and 0min).
The month with the shortest days is December (Average daylight: 9h and 24min).

The month with the most sunshine is June (Average sunshine: 10h and 12min).
The month with the least sunshine is January (Average sunshine: 4h and 6min).

Average sunshine days
Petersburg, IL

Average sunshine days - Petersburg, IL

The month with the most sunshine days is November (18.5 days).
The month with the least sunshine days is May (11.3 days).

Average UV index
Petersburg, IL

Average UV index - Petersburg, 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
Petersburg, IL

Average visibility - Petersburg, IL

The months with the highest visibility are January, February, March, April, May, June, September, October, November and December (6mi).
The months with the lowest visibility are July and August (5mi).

Petersburg, Illinois, USA

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