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
Observing a rise in May, the average high-temperature goes from April's refreshing 65.3°F (18.5°C) to a warm 74.5°F (23.6°C). In O'Fallon, the expected average low-temperature for May is a mild 57°F (13.9°C).Humidity
May is the most humid month, with an average relative humidity of 79%.Rainfall
May is the month with the most rainfall. Rain falls for 15.7 days and accumulates 2.76" (70mm) of precipitation.Snowfall
April through October are months without snowfall.Daylight
In May, the average length of the day is 14h and 19min.On the first day of May, sunrise is at 6:04 am and sunset at 7:55 pm. On the last day of the month, sunrise is at 5:39 am and sunset at 8:21 pm CDT.
Sunshine
In O'Fallon, the average sunshine in May is 9.6h.UV index
May through August, with an average maximum UV index of 6, are months with the highest UV index. A UV Index estimate of 6 to 7 represents a high health risk from exposure to the Sun's UV radiation for the average person.Note: A maximum high daily UV index of 6 during May translates into the following directions:
Refrain from overexposure. Fair-skinned individuals could burn in under 20 minutes. Remember that UV radiation from the Sun is strongest between 10 a.m. and 4 p.m. Make an effort to limit direct sun exposure during this time. Sun protection is enhanced with clothing that boasts a tight weave yet offers a loose fit.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the temperature in May?
What is the most humid month?
What is the average humidity in May?
What is the rainiest month?
How many days does it rain in May?
When it does not snow?
How many hours of daylight does O'Fallon have in May?
When is the sunrise / sunset in May?
How long on average sun shines in May?
When is the highest UV index?
What is the UV index intensity in May?
Average temperature in May
O'Fallon, MO
- Average high temperature in May: 74.5°F
The warmest month (with the highest average high temperature) is July (87.1°F).
The month with the lowest average high temperature is January (37.4°F).
- Average low temperature in May: 57°F
The month with the highest average low temperature is July (68.5°F).
The coldest month (with the lowest average low temperature) is January (23.7°F).
Average pressure in May
O'Fallon, MO
- Average pressure in May: 29.95"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
O'Fallon, MO
- Average wind speed in May: 7.2mph
The windiest month (with the highest average wind speed) is January (9.1mph).
The calmest month (with the lowest average wind speed) is July (5.5mph).
Average humidity in May
O'Fallon, MO
- Average humidity in May: 79%
The month with the highest relative humidity is May (79%).
The month with the lowest relative humidity is October (70%).
Average rainfall in May
O'Fallon, MO
- Average rainfall in May: 2.76"
The wettest month (with the highest rainfall) is May (2.76").
The driest month (with the least rainfall) is December (0.91").
Average rainfall days in May
O'Fallon, MO
- Average rainfall days in May: 15.7 days
The month with the highest number of rainy days is May (15.7 days).
The month with the least rainy days is February (6.8 days).
Average snowfall in May
O'Fallon, MO
- Average snowfall in May: 0"
The month with the highest snowfall is February (1.61").
The months with the least snowfall are April, May, June, July, August, September and October (0").
Average snowfall days in May
O'Fallon, MO
- Average snowfall days in May: 0 days
The months with the highest number of snowfall days are January and February (5.8 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
O'Fallon, MO
- Average daylight in May: 14h and 2min
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 4min
The month with the most sunshine is June (Average sunshine: 10h and 30min).
The months with the least sunshine are January and February (Average sunshine: 4h and 42min).
Average sunshine days in May
O'Fallon, MO
- Average sunshine days in May: 12.9 days
The month with the most sunshine days is December (20.6 days).
The month with the least sunshine days is July (12.6 days).
Average UV index in May
O'Fallon, MO
- 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
O'Fallon, MO
- Average cloud cover in May: 36
The month with the most cloud cover is January (Cloud cover 50).
The months with the least cloud cover are June, July, August and September (Cloud cover 28).
Average visibility in May
O'Fallon, MO
- 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).
O'Fallon, Missouri, USA
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