May weather forecastLanark, IL
May
Weather in May
As May makes its appearance in Illinois, Lanark's climate ascents towards the halcyon summer season. The distinct transition from spring culminates in a dramatic rise in mercury, yet the weather remains quite agreeable. About 14.6 hours of sunlight signifies the days in May gifting citizens with more daylight hours than any other month. This upturn accompanies rainfall of 2.76" (70mm), maintaining the lushness of the city's surrounding. The aura of the city in this month reflects a gradual transition from the soothing touch of spring towards the dry heat of the upcoming summer.Temperature
May's onset brings a temperature rise, moving from a mild 56.5°F (13.6°C) in April to a pleasant 68.5°F (20.3°C). In May, Lanark reports a consistent average low-temperature of 51.4°F (10.8°C) during the nights.Humidity
In Lanark, the average relative humidity in May is 79%.Rainfall
May is the month with the most rainfall. Rain falls for 17.9 days and accumulates 2.76" (70mm) of precipitation.Snowfall
In Lanark, snow does not fall in May through September.Daylight
The average length of the day in May is 14h and 35min.On the first day of the month, sunrise is at 5:53 am and sunset at 7:58 pm. On the last day of May, sunrise is at 5:25 am and sunset at 8:28 pm CDT.
Sunshine
In Lanark, the average sunshine in May is 8.5h.UV index
In May, the average daily maximum UV index in Lanark is 5. A UV Index estimate of 3 to 5 represents a moderate health risk from exposure to the Sun's UV radiation for average individuals.Note: A typical high UV index of 5 in May suggests the following recommendations:
Be vigilant - A duty to shield skin and eyes from injury exists. Minimize direct exposure to the Sun during midday when its radiation is at its peak. A wide-brimmed hat is a staple for defending the face, eyes, ears, and neck from the Sun.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in May
Lanark, IL
- Average high temperature in May: 68.5°F
The warmest month (with the highest average high temperature) is July (79.9°F).
The month with the lowest average high temperature is January (25.9°F).
- Average low temperature in May: 51.4°F
The month with the highest average low temperature is July (63.3°F).
The coldest month (with the lowest average low temperature) is January (13.5°F).
Average pressure in May
Lanark, IL
- Average pressure in May: 29.95"Hg
The month with the highest atmospheric pressure is January (30.12"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).
Average wind speed in May
Lanark, IL
- Average wind speed in May: 8.8mph
The windiest month (with the highest average wind speed) is April (10.4mph).
The calmest month (with the lowest average wind speed) is August (6.5mph).
Average humidity in May
Lanark, IL
- Average humidity in May: 79%
The month with the highest relative humidity is January (87%).
The month with the lowest relative humidity is October (75%).
Average rainfall in May
Lanark, IL
- Average rainfall in May: 2.76"
The wettest month (with the highest rainfall) is May (2.76").
The driest months (with the least rainfall) are January and February (0.71").
Average rainfall days in May
Lanark, IL
- Average rainfall days in May: 17.9 days
The month with the highest number of rainy days is May (17.9 days).
The month with the least rainy days is February (4.4 days).
Average snowfall in May
Lanark, IL
- Average snowfall in May: 0"
The month with the highest snowfall is January (2.64").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in May
Lanark, IL
- Average snowfall days in May: 0 days
The month with the highest number of snowfall days is January (11.2 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
Lanark, IL
- Average daylight in May: 14h and 36min
The month with the longest days is June (Average daylight: 15h and 12min).
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 July (Average sunshine: 9h and 48min).
The month with the least sunshine is January (Average sunshine: 3h and 42min).
Average sunshine days in May
Lanark, IL
- Average sunshine days in May: 11.6 days
The month with the most sunshine days is November (19.7 days).
The month with the least sunshine days is June (10 days).
Average UV index in May
Lanark, IL
- Average UV index in May: 5
The month with the highest UV index is July (UV index 6).
The months with the lowest UV index are January and December (UV index 1).
Average cloud cover in May
Lanark, IL
- Average cloud cover in May: 43
The month with the most cloud cover is January (Cloud cover 61).
The month with the least cloud cover is September (Cloud cover 32).
Average visibility in May
Lanark, IL
- Average visibility in May: 6mi
The months with the highest visibility are February, March, April, May, June, September, October, November and December (6mi).
The months with the lowest visibility are January, July and August (5mi).





