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
Decatur's weather in May shows a rise in the average high-temperature, moving up from April's enjoyable 61.9°F (16.6°C) to an agreeable 72.9°F (22.7°C). An average low-temperature of 56.7°F (13.7°C) is observed during May nights.Humidity
The average relative humidity in May is 77%.Rainfall
May is the month with the most rainfall. Rain falls for 17 days and accumulates 2.01" (51mm) of precipitation.Snowfall
In Decatur, snow does not fall in May through October.Daylight
In Decatur, the average length of the day in May is 14h and 23min.On the first day of May, sunrise is at 5:55 am and sunset at 7:50 pm. On the last day of the month, sunrise is at 5:29 am and sunset at 8:17 pm CDT.
Sunshine
In Decatur, Illinois, the average sunshine in May is 9.3h.UV index
The average daily maximum UV index in May is 5. A UV Index estimate of 3 to 5 represents a medium vulnerability from exposure to the Sun's UV rays for average individuals.Note: The daily maximum UV index of 5 in May interprets into the following advice:
Undertake precautions - Guarding against sun damage is counselled. Solar radiation is at its peak intensity during midday, so it's advisable to stay indoors or in the shade. Wearing a wide-brim hat can block approximately 50% of UV radiation, protecting the eyes.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the average May temperature in Decatur?
What is the average humidity in May in Decatur?
What is the rainiest month in Decatur?
How much does it rain in Decatur in May?
When it does not snow in Decatur?
Does it snow in Decatur in May?
How many hours of daylight does Decatur have in May?
When are sunrise and sunset in May in Decatur?
How long on average sun shines in May in Decatur?
How high is the UV index in May in Decatur?
Average temperature in May
Decatur, IL
- Average high temperature in May: 72.9°F
The warmest month (with the highest average high temperature) is July (82°F).
The month with the lowest average high temperature is January (32.9°F).
- Average low temperature in May: 56.7°F
The month with the highest average low temperature is July (65.7°F).
The coldest month (with the lowest average low temperature) is January (21.2°F).
Average pressure in May
Decatur, IL
- Average pressure in May: 29.96"Hg
The month with the highest atmospheric pressure is January (30.15"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).
Average wind speed in May
Decatur, IL
- Average wind speed in May: 8.8mph
The windiest month (with the highest average wind speed) is January (10.7mph).
The calmest months (with the lowest average wind speed) are July and August (6.3mph).
Average humidity in May
Decatur, IL
- Average humidity in May: 77%
The month with the highest relative humidity is July (84%).
The month with the lowest relative humidity is October (70%).
Average rainfall in May
Decatur, IL
- Average rainfall in May: 2.01"
The wettest month (with the highest rainfall) is May (2.01").
The driest months (with the least rainfall) are February and December (0.87").
Average rainfall days in May
Decatur, IL
- Average rainfall days in May: 17 days
The month with the highest number of rainy days is May (17 days).
The month with the least rainy days is February (5.8 days).
Average snowfall in May
Decatur, IL
- Average snowfall in May: 0"
The month with the highest snowfall is January (1.85").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in May
Decatur, IL
- Average snowfall days in May: 0 days
The month with the highest number of snowfall days is January (7.2 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).
Average daylight in May /
Average sunshine in May
Decatur, IL
- Average daylight in May: 14h and 2min
The month with the longest days is June (Average daylight: 15h and 0min).
The month with the shortest days is December (Average daylight: 9h and 24min).
- Average sunshine in May: 9h and 2min
The month with the most sunshine is June (Average sunshine: 10h and 24min).
The month with the least sunshine is January (Average sunshine: 4h and 6min).
Average sunshine days in May
Decatur, IL
- Average sunshine days in May: 11.5 days
The month with the most sunshine days is October (19.8 days).
The month with the least sunshine days is May (11.5 days).
Average UV index in May
Decatur, 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, February, November and December (UV index 2).
Average cloud cover in May
Decatur, IL
- Average cloud cover in May: 39
The month with the most cloud cover is January (Cloud cover 56).
The month with the least cloud cover is September (Cloud cover 29).
Average visibility in May
Decatur, IL
- Average visibility in May: 6mi
The months with the highest visibility are January, February, March, April, May, June, September, October, November and December (6mi).
The months with the lowest visibility are July and August (5mi).
Decatur, Illinois, USA
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