Contents
- Weather in May
- Frequently asked questions
- Average temperature in May
- Average pressure in May
- Average wind speed in May
- Average humidity in May
- Average rainfall in May
- Average rainfall days in May
- Average snowfall in May
- Average snowfall days in May
- Average daylight in May
- Average sunshine in May
- Average sunshine days in May
- Average UV index in May
- Average cloud cover in May
- Average visibility in May
Weather in May
Temperature
In River Forest, the average high-temperature in May increases from a fresh 53.2°F (11.8°C) in April to an enjoyable 64.4°F (18°C). Throughout the month of May, the nighttime temperature dips to an average of 51.4°F (10.8°C).Humidity
In May, the average relative humidity is 77%.Rainfall
May is the month with the most rainfall. Rain falls for 18.8 days and accumulates 4.49" (114mm) of precipitation.Snowfall
January through May, October through December are months with snowfall. May is the last month it regularly snows. During 0.1 snowfall days, in May, River Forest aggregates 0.08" (2mm) of snow. In River Forest, during the entire year, snow falls for 40.3 days and aggregates up to 16.81" (427mm) of snow.Daylight
In River Forest, the average length of the day in May is 14h and 34min.On the first day of the month, sunrise is at 5:46 am and sunset at 7:50 pm. On the last day of May, sunrise is at 5:18 am and sunset at 8:19 pm CDT.
Sunshine
The average sunshine in May is 8.7h.UV index
The average daily maximum UV index in May is 5. A UV Index estimate of 3 to 5 represents a moderate threat to health from unsafe exposure to UV radiation for the average person.Note: A daily high UV index of 5 in May leads to these guidelines:
Exercise prevention - Warding off sunburn is urged. The solar radiation around mid-day is intense; avoid the Sun and stay safe. Wearing sunglasses with both UVA and UVB protection effectively reduces sun-induced eye damage. Stay alert! Snow's reflective properties can almost double the UV radiation from the Sun.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the average May temperature in River Forest?
What is the average humidity in May?
What is the rainiest month?
How much does it rain in May?
What is the last month it snows?
How many hours of daylight does River Forest have in May?
What time are sunrise and sunset in May?
How long on average sun shines in May?
What is the UV index intensity in May?
Average temperature in May
River Forest, IL
- Average high temperature in May: 64.4°F
The warmest month (with the highest average high temperature) is July (79.7°F).
The month with the lowest average high temperature is January (28.9°F).
- Average low temperature in May: 51.4°F
The month with the highest average low temperature is July (67.5°F).
The coldest month (with the lowest average low temperature) is January (19.4°F).
Average pressure in May
River Forest, IL
- Average pressure in May: 29.96"Hg
The month with the highest atmospheric pressure is January (30.11"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).
Average wind speed in May
River Forest, IL
- Average wind speed in May: 8.7mph
The windiest month (with the highest average wind speed) is January (11.1mph).
The calmest months (with the lowest average wind speed) are July and August (7mph).
Average humidity in May
River Forest, IL
- Average humidity in May: 77%
The month with the highest relative humidity is January (82%).
The month with the lowest relative humidity is October (72%).
Average rainfall in May
River Forest, IL
- Average rainfall in May: 4.49"
The wettest month (with the highest rainfall) is May (4.49").
The driest month (with the least rainfall) is December (1.57").
Average rainfall days in May
River Forest, IL
- Average rainfall days in May: 18.8 days
The month with the highest number of rainy days is May (18.8 days).
The month with the least rainy days is February (5.1 days).
Average snowfall in May
River Forest, IL
- Average snowfall in May: 0.08"
The month with the highest snowfall is February (4.69").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in May
River Forest, IL
- Average snowfall days in May: 0.1 days
The month with the highest number of snowfall days is January (10.8 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in May /
Average sunshine in May
River Forest, IL
- Average daylight in May: 14h and 4min
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 4min
The month with the most sunshine is August (Average sunshine: 10h and 36min).
The month with the least sunshine is January (Average sunshine: 3h and 42min).
Average sunshine days in May
River Forest, IL
- Average sunshine days in May: 10.4 days
The month with the most sunshine days is December (16.7 days).
The month with the least sunshine days is July (9.9 days).
Average UV index in May
River Forest, IL
- Average UV index in May: 5
The months with the highest UV index are June, July and August (UV index 6).
The months with the lowest UV index are January and December (UV index 1).
Average cloud cover in May
River Forest, IL
- Average cloud cover in May: 41
The month with the most cloud cover is January (Cloud cover 61).
The month with the least cloud cover is August (Cloud cover 27).
Average visibility in May
River Forest, 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).
River Forest, Illinois, USA
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