May weather forecastCaseyville, IL
May
Weather in May
The last month of the spring, May, is a warm month in Caseyville, Illinois, with temperature in the range of an average low of 57.6°F (14.2°C) and an average high of 74.5°F (23.6°C).Temperature
An escalation in the average high-temperature is seen with the onset of May, moving from a refreshing 64.9°F (18.3°C) in April to a warm 74.5°F (23.6°C). The average temperature during May nights dips to a refreshing 57.6°F (14.2°C).Humidity
May, July and August, with an average relative humidity of 79%, are the most humid months.Rainfall
The month with the most rainfall is May, when the rain falls for 17.1 days and typically aggregates up to 4.17" (106mm) of precipitation.Snowfall
April through August and October are months without snowfall.Daylight
In May, the average length of the day is 14h and 17min.On the first day of May in Caseyville, sunrise is at 6:01 am and sunset at 7:52 pm. On the last day of the month, sunrise is at 5:37 am and sunset at 8:18 pm CDT.
Sunshine
In Caseyville, the average sunshine in May is 9.4h.UV index
May through August, with an average maximum UV index of 6, are months with the highest UV index. A UV Index value of 6 to 7 symbolizes a high health vulnerability from unprotected exposure to Sun's UV rays for average individuals.Note: In May, the maximum UV index of 6 transforms into these recommendations:
Persist with precautions and heed sun safety advice. Prevention of sunburn is compulsory. Between 10 a.m. and 4 p.m., the Sun's UV radiation is at its peak. Limit your exposure to direct sunlight during these hours. For excellent sun protection for the eyes, ears, face, and neck, consider a wide-brim hat.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in May
Caseyville, IL
- Average high temperature in May: 74.5°F
The warmest month (with the highest average high temperature) is July (85.6°F).
The month with the lowest average high temperature is January (37.4°F).
- Average low temperature in May: 57.6°F
The month with the highest average low temperature is July (68.2°F).
The coldest month (with the lowest average low temperature) is January (24.3°F).
Average pressure in May
Caseyville, IL
- Average pressure in May: 29.96"Hg
The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).
Average wind speed in May
Caseyville, IL
- Average wind speed in May: 7.5mph
The windiest month (with the highest average wind speed) is January (9.5mph).
The calmest month (with the lowest average wind speed) is July (5.6mph).
Average humidity in May
Caseyville, IL
- Average humidity in May: 79%
The months with the highest relative humidity are May, July and August (79%).
The month with the lowest relative humidity is October (71%).
Average rainfall in May
Caseyville, IL
- Average rainfall in May: 4.17"
The wettest month (with the highest rainfall) is May (4.17").
The driest month (with the least rainfall) is February (1.77").
Average rainfall days in May
Caseyville, IL
- Average rainfall days in May: 17.1 days
The month with the highest number of rainy days is May (17.1 days).
The month with the least rainy days is January (7.8 days).
Average snowfall in May
Caseyville, IL
- Average snowfall in May: 0"
The month with the highest snowfall is January (2.13").
The months with the least snowfall are April, May, June, July, August and October (0").
Average snowfall days in May
Caseyville, IL
- Average snowfall days in May: 0 days
The month with the highest number of snowfall days is January (7 days).
The months with the least snowfall days are May, June, July and August (0 days).
Average daylight in May /
Average sunshine in May
Caseyville, IL
- Average daylight in May: 14h and 18min
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).
- Average sunshine in May: 9h and 24min
The month with the most sunshine is June (Average sunshine: 10h and 30min).
The month with the least sunshine is January (Average sunshine: 4h and 30min).
Average sunshine days in May
Caseyville, IL
- Average sunshine days in May: 11.6 days
The month with the most sunshine days is December (18.6 days).
The month with the least sunshine days is May (11.6 days).
Average UV index in May
Caseyville, IL
- Average UV index in May: 6
The months with the highest UV index are May, June, July and August (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 2).
Average cloud cover in May
Caseyville, IL
- Average cloud cover in May: 38
The month with the most cloud cover is January (Cloud cover 51).
The months with the least cloud cover are June and August (Cloud cover 28).
Average visibility in May
Caseyville, IL
- Average visibility in May: 6mi
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).





