Climate and monthly weather forecast
Sumner, IL

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Weather in January

January, like December, in Sumner, Illinois, is a wintry winter month, with an average temperature varying between 36.7°F (2.6°C) and 24.4°F (-4.2°C). Sumner, Illinois, reaches its lowest average temperatures in January, measuring 36.7°F (2.6°C) at the peak and 24.4°F (-4.2°C) at the lowest. Weather in January »

Weather in February

The last month of the winter, February, is also a wintry month in Sumner, Illinois, with an average temperature fluctuating between 41.9°F (5.5°C) and 28.2°F (-2.1°C). An average high-temperature of a still icy 41.9°F (5.5°C) marks February, exhibiting a close resemblance to the conditions in January. Weather in February »

Weather in March

March, the first month of the spring in Sumner, is a fresh month, with an average temperature varying between 37.8°F (3.2°C) and 53.1°F (11.7°C). March signals a shift in the average high-temperature, moving from February's cold 41.9°F (5.5°C) to a cool 53.1°F (11.7°C). Weather in March »

Weather in April

April in Sumner, Illinois, is a refreshing spring month, with an average temperature varying between 64.4°F (18°C) and 47.7°F (8.7°C). In Sumner, the average high-temperature in April increases from a fresh 53.1°F (11.7°C) in March to an enjoyable 64.4°F (18°C). Weather in April »

Weather in May

May, the last month of the spring in Sumner, is a moderately hot month, with an average temperature ranging between max 73.9°F (23.3°C) and min 57.7°F (14.3°C). Sumner sees an increase in the average high-temperature with the arrival of May, moving from April's enjoyable 64.4°F (18°C) to a warm 73.9°F (23.3°C). Weather in May »

Weather in June

The first month of the summer, June, is still a warm month in Sumner, Illinois, with temperature in the range of an average high of 82°F (27.8°C) and an average low of 65.5°F (18.6°C). The start of June brings a subtle shift in the average high-temperature, edging up from May's 73.9°F (23.3°C) to a still moderately hot 82°F (27.8°C). Weather in June »

Weather in July

July, the same as June, is another warm summer month in Sumner, Illinois, with an average temperature fluctuating between 84°F (28.9°C) and 67.3°F (19.6°C). In Sumner, July is the warmest month, with temperatures averaging a high of 84°F (28.9°C) and a low of 67.3°F (19.6°C). July's heat index is calculated to be a very hot 95°F (35°C). Weather in July »

Weather in August

The last month of the summer, August, is another warm month in Sumner, Illinois, with an average temperature varying between 82.9°F (28.3°C) and 65.7°F (18.7°C). In Sumner, August's average high-temperature stands at a still warm 82.9°F (28.3°C), closely related to the preceding month. Weather in August »

Weather in September

The first month of the autumn, September, is also a moderately hot month in Sumner, Illinois, with an average temperature fluctuating between 78.3°F (25.7°C) and 60.1°F (15.6°C). September registers an average high-temperature of a still warm 78.3°F (25.7°C), slightly varied from August's 82.9°F (28.3°C). Weather in September »

Weather in October

October, like September, in Sumner, Illinois, is another enjoyable autumn month, with an average temperature ranging between min 49.3°F (9.6°C) and max 66°F (18.9°C). Welcoming October, Sumner observes a shift in the average high-temperature, falling from September's moderately hot 78.3°F (25.7°C) to an enjoyable 66°F (18.9°C). Weather in October »

Weather in November

The last month of the autumn, November, is another cool month in Sumner, Illinois, with an average temperature ranging between max 52.2°F (11.2°C) and min 37.9°F (3.3°C). November suggests a modest reduction in the average high-temperature, shifting from a refreshing 66°F (18.9°C) in October to a fresh 52.2°F (11.2°C). Weather in November »

Weather in December

The first month of the winter, December, is still a cold month in Sumner, Illinois, with an average temperature varying between 30.9°F (-0.6°C) and 41.9°F (5.5°C). A subtle decrease in the average high-temperature marks December, falling from November's fresh 52.2°F (11.2°C) to a cold 41.9°F (5.5°C). Weather in December »
Updated: Feb 12, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the coldest time of year in Sumner?

Sumner witnesses the coldest weather in January, with temperatures averaging a high of 36.7°F (2.6°C) and a low of 24.4°F (-4.2°C).

How much does it rain in Sumner?

In Sumner, during the entire year, the rain falls for 160.3 days and collects up to 34.33" (872mm) of precipitation.

When does it snow in Sumner?

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

When does it snow the most in Sumner?

The month with the most snowfall in Sumner is January, when snow falls for 6.8 days and typically aggregates up to 1.69" (43mm) of snow.

How many days does it snow in Sumner?

Throughout the year, in Sumner, there are 21.7 snowfall days, and 5.87" (149mm) of snow is accumulated.

What is the month with the least sunshine in Sumner?

The month with the least sunshine is January, with an average of 4.4h of sunshine.

When is the lowest UV index in Sumner?

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

When is Daylight Saving Time (DST) in Sumner?

On Sunday, March 10. 2024, at 2:00 am, Daylight Saving Time starts in Sumner, Illinois, 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 Sumner?

April is the month with the most rainfall in Sumner, Illinois. Rain falls for 15.8 days and accumulates 4.69" (119mm) of precipitation.

When it does not snow in Sumner?

May through October are months without snowfall.

When are the longest days in Sumner?

The month with the longest days is June, with an average of 14h and 48min of daylight.

What month has the most sunshine in Sumner?

June has the most sunshine of the year in Sumner, with an average of 10.6h of sunshine.

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

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

What are the warmest months in Sumner?

Sumner's warmest temperatures are experienced in July, with average high temperatures of 84°F (28.9°C) and lows of 67.3°F (19.6°C).

What is the most humid month in Sumner?

With an average relative humidity of 81%, July is the most humid month in Sumner.

What is the driest month in Sumner?

September is the month with the least rainfall. Rain falls for 13.1 days and accumulates 1.93" (49mm) of precipitation.

What is the least humid month in Sumner?

October is the least humid month, with an average relative humidity of 70%.

What is the month with the shortest days in Sumner?

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

Average temperature
Sumner, IL

Average temperature - Sumner, IL

The warmest month (with the highest average high temperature) is July (84°F).
The month with the lowest average high temperature is January (36.7°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 (24.4°F).

Average pressure
Sumner, IL

Average pressure - Sumner, IL

The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.94"Hg).

Average wind speed
Sumner, IL

Average wind speed - Sumner, IL

The windiest month (with the highest average wind speed) is February (10.1mph).
The calmest month (with the lowest average wind speed) is July (5.8mph).

Average rainfall
Sumner, IL

Average rainfall - Sumner, IL

The wettest month (with the highest rainfall) is April (4.69").
The driest month (with the least rainfall) is September (1.93").

Average rainfall days
Sumner, IL

Average rainfall days - Sumner, IL

The month with the highest number of rainy days is May (19.6 days).
The month with the least rainy days is February (9.4 days).

Average snowfall
Sumner, IL

Average snowfall - Sumner, IL

The month with the highest snowfall is January (1.69").
The months with the least snowfall are May, June, July, August, September and October (0").

Average snowfall days
Sumner, IL

Average snowfall days - Sumner, IL

The month with the highest number of snowfall days is January (6.8 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).

Average daylight / Average sunshine
Sumner, IL

Average daylight / Average sunshine - Sumner, IL

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).

The month with the most sunshine is June (Average sunshine: 10h and 36min).
The month with the least sunshine is January (Average sunshine: 4h and 24min).

Average sunshine days
Sumner, IL

Average sunshine days - Sumner, IL

The month with the most sunshine days is October (18 days).
The month with the least sunshine days is May (9.4 days).

Average UV index
Sumner, IL

Average UV index - Sumner, 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
Sumner, IL

Average visibility - Sumner, 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).

Sumner, Illinois, USA

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