Joliet
Illinois, USA
Long-term weather forecast
Long-term weather forecast

Monthly weather forecast and climate
Joliet, IL

 A unique shot of cars, trees, and buildings along a street in the town of Joliet, Illinois, with a view of the clear blue sky above
A unique shot of cars, trees, and buildings along a street in the town of Joliet, Illinois, with a view of the clear blue sky above
January, like December, is a freezing cold winter month in Joliet, Illinois, with temperature in the range of an average low of 17.4°F (-8.1°C) and an average high of 29.3°F (-1.5°C). The coldest month is January, with an average high-temperature of 29.3°F (-1.5°C) and an average low-temperature of 17.4°F (-8.1°C). Weather in January »

February, the last month of the winter, in Joliet, is a cold month, with average temperature varying between 33.4°F (0.8°C) and 20.7°F (-6.3°C). In February, the average high-temperature is relatively the same as in January - a cold 33.4°F (0.8°C). Weather in February »

The first month of the spring, March, is a chilly month in Joliet, Illinois, with average temperature ranging between max 46.2°F (7.9°C) and min 31.8°F (-0.1°C). In March, the average high-temperature increases, from a wintry 33.4°F (0.8°C) in February, to a chilly 46.2°F (7.9°C). Weather in March »

April is a moderate spring month in Joliet, Illinois, with average temperature fluctuating between 41.7°F (5.4°C) and 58.1°F (14.5°C). In April, the average high-temperature increases, from a frosty 46.2°F (7.9°C) in March, to a mild 58.1°F (14.5°C). Weather in April »

May, the last month of the spring, in Joliet, is a pleasant month, with average temperature ranging between max 70.3°F (21.3°C) and min 52.3°F (11.3°C). In Joliet, Illinois, the average high-temperature in May rises, from a moderate 58.1°F (14.5°C) in April, to an agreeable 70.3°F (21.3°C). Weather in May »

June, the first month of the summer, in Joliet, is a moderately hot month, with average temperature fluctuating between 61.3°F (16.3°C) and 79.2°F (26.2°C). In Joliet, Illinois, the average high-temperature marginally rises, from an agreeable 70.3°F (21.3°C) in May, to a moderately hot 79.2°F (26.2°C). Weather in June »

July, the same as June, is a moderately hot summer month in Joliet, Illinois, with temperature in the range of an average high of 81.3°F (27.4°C) and an average low of 64.8°F (18.2°C). With an average high-temperature of 81.3°F (27.4°C) and an average low-temperature of 64.8°F (18.2°C), July is the warmest month. The average heat index is calculated to a tropical 87.6°F (30.9°C). Weather in July »

August, the last month of the summer, in Joliet, is also a moderately hot month, with average temperature varying between 62.8°F (17.1°C) and 80.1°F (26.7°C). In Joliet, the average high-temperature is relatively the same as in July - a still moderately hot 80.1°F (26.7°C). Weather in August »

The first month of the autumn, September, is also a moderately hot month in Joliet, Illinois, with average temperature ranging between max 74.7°F (23.7°C) and min 56.7°F (13.7°C). In September, the average high-temperature marginally drops, from 80.1°F (26.7°C) in August, to a still moderately hot 74.7°F (23.7°C). Weather in September »

October, like September, in Joliet, Illinois, is another enjoyable autumn month, with average temperature fluctuating between 45.5°F (7.5°C) and 61.3°F (16.3°C). In October, the average high-temperature drops, from a warm 74.7°F (23.7°C) in September, to a comfortable 61.3°F (16.3°C). Weather in October »

November, the last month of the autumn, in Joliet, is also a frosty month, with average temperature ranging between min 33.4°F (0.8°C) and max 47.1°F (8.4°C). In Joliet, the average high-temperature drops, from an enjoyable 61.3°F (16.3°C) in October, to a frosty 47.1°F (8.4°C). Weather in November »

December, the first month of the winter, in Joliet, is also a wintry month, with average temperature ranging between max 35.1°F (1.7°C) and min 25°F (-3.9°C). In December, the average high-temperature decreases, from a frosty 47.1°F (8.4°C) in November, to a wintry 35.1°F (1.7°C). Weather in December »

What is the coldest month in Joliet?

With an average high-temperature of 29.3°F (-1.5°C) and an average low-temperature of 17.4°F (-8.1°C), January is the coldest month.

How much does it rain in Joliet?

Throughout the year, in Joliet, Illinois, there are 153.6 rainfall days, and 32.72" (831mm) of precipitation is accumulated.

When does it snow in Joliet?

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

How many days does it snow in Joliet?

In Joliet, during the entire year, snow falls for 38.2 days, and aggregates up to 14.61" (371mm) of snow.

When does it snow the most in Joliet?

January is the month with the most snowfall in Joliet, Illinois. Snow falls for 11.9 days and accumulates 4.33" (110mm) of snow.

What is the month with the least sunshine in Joliet?

January has the least sunshine of the year, with an average of 3.7h of sunshine.

When is the lowest UV index in Joliet?

Months with the lowest UV index in Joliet, Illinois, are January and December, with an average maximum UV index of 1.

What is the most humid month in Joliet?

The most humid month in Joliet is February, with an average relative humidity of 83%.

What is the driest month in Joliet?

February is the month with the least rainfall. Rain falls for 5.7 days and accumulates 1.61" (41mm) of precipitation.

What is the rainiest month in Joliet?

May is the month with the most rainfall in Joliet, Illinois. Rain falls for 17.8 days and accumulates 4.41" (112mm) of precipitation.

When it does not snow in Joliet?

In Joliet, Illinois, snow does not fall in May through October.

When are the longest days in Joliet?

The month with the longest days in Joliet, Illinois, is June, with an average of 15.1h of daylight.

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

June and July, with an average maximum UV index of 6, are months with the highest UV index in Joliet, Illinois.

What is the warmest month in Joliet?

With an average high-temperature of 81.3°F (27.4°C) and an average low-temperature of 64.8°F (18.2°C), July is the warmest month in Joliet.

What month has the most sunshine in Joliet?

The month with the most sunshine is August, with an average of 9.7h of sunshine.

What is the least humid month in Joliet?

With an average relative humidity of 73%, October is the least humid month.

What is the month with the shortest days in Joliet?

The month with the shortest days is December, with an average of 9.2h of daylight.
Average temperature - Joliet, IL
Average rainfall - Joliet, IL

The wettest month (with the highest rainfall) is May (4.41").
The driest month (with the lowest rainfall) is February (1.61").

Average rainfall days - Joliet, IL

The month with the highest number of rainy days is July (17.9 days).
The month with the lowest number of rainy days is February (5.7 days).

Average snowfall - Joliet, IL
Average snowfall days - Joliet, IL

The month with the highest number of snowfall days is January (11.9 days).
Months with the lowest number of snowfall days are May, June, July, August and September (0 days).

Average daylight / Average sunshine - Joliet, IL