May weather forecastJoliet, IL
May
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.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
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: 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: 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: 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: 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: 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: 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: 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: 14h and 30min
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 30min
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: 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: 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: 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: 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).
