May weather forecast
Joliet, IL

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A unique shot of cars, trees, and buildings along a street in the town of Joliet, Illinois
A unique shot of cars, trees, and buildings along a street in the town of Joliet, Illinois

Weather in May

May in Joliet welcomes warmer weather and the onset of the city's rainiest month with 4.41" (112mm) of rainfall recorded. The change in season is accompanied by a noticeable leap in temperature, bringing longer daylight hours and consequently more sunshine. The climate during this month is characterized by mild, soft winds and lowered cloud coverage, favoring a good visibility distance. Albeit sporadic, humidity levels tend to fluctuate, implying a transition to a more humid environment.

Temperature

Joliet's transition into May sees a rise in the average high-temperature, advancing from a refreshing 58.1°F (14.5°C) in April to an agreeable 70.3°F (21.3°C). Throughout May, Joliet witnesses a consistent average low-temperature of 52.3°F (11.3°C).

Humidity

The average relative humidity in May is 77%.

Rainfall

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

Snowfall

May through October are months without snowfall.

Daylight

In May, the average length of the day in Joliet is 14h and 32min.
On the first day of May, sunrise is at 5:48 am and sunset at 7:50 pm. On the last day of the month, sunrise is at 5:20 am and sunset at 8:19 pm CDT.

Sunshine

The average sunshine in May is 8.5h.

UV index

The average daily maximum UV index in May is 5. A UV Index of 3 to 5 symbolizes a moderate threat to health from unsafe exposure to UV radiation for the average person.
Note: A maximum UV index of 5 in May translates into the following recommendations:
Be vigilant - Preventing sunburn is recommended. Stay safe from the Sun's strongest UV rays by limiting exposure during midday. For effective sun eye protection, rely on sunglasses certified for UVA and UVB resistance.

Frequently asked questions

What is the usual temperature for Joliet in May?

In May, the average high-temperature and low-temperature are 70.3°F (21.3°C) and 52.3°F (11.3°C) respectively.

What is the average humidity in May?

The average relative humidity in May is 77%.

What is the wettest month?

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

How much does it rain in May?

In Joliet, in May, it is raining for 17.8 days, with typically 4.41" (112mm) of accumulated precipitation.

When it does not snow?

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

Does it snow in May?

In May, it doesn't snow. April is the latest month when it typically snows.

What is the average length of the day in May?

The average day length in May is 14h and 32min.

When is the sunrise / sunset in May?

In May, on the first day of the month, sunrise is at 5:48 am and sunset at 7:50 pm. On the last day of the month, sunrise is at 5:20 am and sunset at 8:19 pm CDT.

How many hours of sunshine does Joliet have in May?

In Joliet, the average sunshine duration in May is 8.5h.

What is the UV index intensity in May?

The average daily maximum UV index in May in Joliet is 5. A UV Index value of 3 to 5 symbolizes a medium hazard to health from unprotected exposure to UV radiation.
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 May
Joliet, IL

Average temperature in May - Joliet, IL
  • Average high temperature in May: 70.3°F

The warmest month (with the highest average high temperature) is July (81.3°F).
The month with the lowest average high temperature is January (29.3°F).

  • Average low temperature in May: 52.3°F

The month with the highest average low temperature is July (64.8°F).
The coldest month (with the lowest average low temperature) is January (17.4°F).

Average pressure in May
Joliet, IL

Average pressure in May - Joliet, IL
  • Average pressure in May: 29.96"Hg

The month with the highest atmospheric pressure is January (30.12"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).

Average wind speed in May
Joliet, IL

Average wind speed in May - Joliet, IL
  • Average wind speed in May: 8.3mph

The windiest month (with the highest average wind speed) is April (9.7mph).
The calmest month (with the lowest average wind speed) is August (5.9mph).

Average humidity in May
Joliet, IL

Average humidity in May - Joliet, IL
  • Average humidity in May: 77%

The month with the highest relative humidity is February (83%).
The month with the lowest relative humidity is October (73%).

Average rainfall in May
Joliet, IL

Average rainfall in May - Joliet, IL
  • Average rainfall in May: 4.41"

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

Average rainfall days in May
Joliet, IL

Average rainfall days in May - Joliet, IL
  • Average rainfall days in May: 17.8 days

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

Average snowfall in May
Joliet, IL

Average snowfall in May - Joliet, IL
  • Average snowfall in May: 0"

The month with the highest snowfall is January (4.33").
The months with the least snowfall are May, June, July, August, September and October (0").

Average snowfall days in May
Joliet, IL

Average snowfall days in May - Joliet, IL
  • Average snowfall days in May: 0 days

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

Average daylight in May /
Average sunshine in May
Joliet, IL

Average daylight in May / Average sunshine in May - Joliet, IL
  • Average daylight in May: 14h and 3min

The month with the longest days is June (Average daylight: 15h and 6min).
The month with the shortest days is December (Average daylight: 9h and 12min).

  • Average sunshine in May: 8h and 3min

The month with the most sunshine is August (Average sunshine: 9h and 42min).
The month with the least sunshine is January (Average sunshine: 3h and 42min).

Average sunshine days in May
Joliet, IL

Average sunshine days in May - Joliet, IL
  • Average sunshine days in May: 11.6 days

The month with the most sunshine days is November (18.1 days).
The month with the least sunshine days is June (10.4 days).

Average UV index in May
Joliet, IL

Average UV index in May - Joliet, IL
  • Average UV index in May: 5

The months with the highest UV index are June and July (UV index 6).
The months with the lowest UV index are January and December (UV index 1).

Average cloud cover in May
Joliet, IL

Average cloud cover in May - Joliet, IL
  • Average cloud cover in May: 43

The month with the most cloud cover is January (Cloud cover 60).
The months with the least cloud cover are August and September (Cloud cover 34).

Average visibility in May
Joliet, IL

Average visibility in May - Joliet, IL
  • Average visibility in May: 6mi

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

Joliet, Illinois, USA

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