May weather forecastWilliamson, IA
May
Weather in May
The last month of the spring, May, is an agreeable month in Williamson, Iowa, with an average temperature ranging between max 69.4°F (20.8°C) and min 52.7°F (11.5°C).Temperature
As Williamson enters May, the average high-temperature increases from the a mild 60.1°F (15.6°C) of April to a pleasant 69.4°F (20.8°C). During May, the temperature is averaged to a low of 52.7°F (11.5°C) at night.Humidity
The average relative humidity in May in Williamson, Iowa, is 81%.Rainfall
In May, in Williamson, the rain falls for 16.7 days. Throughout May, 3.7" (94mm) of precipitation is accumulated. In Williamson, Iowa, during the entire year, the rain falls for 131.1 days and collects up to 25.71" (653mm) of precipitation.Snowfall
Months with snowfall in Williamson are January through May, October through December. May is the last month it regularly snows. During 0.3 snowfall days, in May, Williamson aggregates 0.28" (7mm) of snow. Throughout the year, there are 33.4 snowfall days, and 13.54" (344mm) of snow is accumulated.Daylight
The average length of the day in May in Williamson is 14h and 30min.On the first day of May in Williamson, sunrise is at 6:09 am and sunset at 8:10 pm. On the last day of the month, sunrise is at 5:42 am and sunset at 8:38 pm CDT.
Sunshine
In Williamson, the average sunshine in May is 8.5h.UV index
In Williamson, Iowa, the average daily maximum UV index in May is 5. A UV Index of 3 to 5 symbolizes a medium health hazard from unsafe exposure to UV radiation for the average person.Note: The maximum daily UV index, 5 in May, converts into the following recommendations:
Adopt protective measures - Requirement to safeguard skin and eyes from harm exists. To prevent harmful UV exposure, minimize direct contact with the Sun around midday. Stay sun-safe with clothing that is both closely woven and worn loosely. Be alert! Nearly double the UV rays from the Sun can be reflected by snow.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in May
Williamson, IA
- Average high temperature in May: 69.4°F
The warmest month (with the highest average high temperature) is July (83.1°F).
The month with the lowest average high temperature is January (29.3°F).
- Average low temperature in May: 52.7°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 (16°F).
Average pressure in May
Williamson, IA
- Average pressure in May: 29.93"Hg
The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.89"Hg).
Average wind speed in May
Williamson, IA
- Average wind speed in May: 8.9mph
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 (7.1mph).
Average humidity in May
Williamson, IA
- Average humidity in May: 81%
The month with the highest relative humidity is June (83%).
The month with the lowest relative humidity is October (72%).
Average rainfall in May
Williamson, IA
- Average rainfall in May: 3.7"
The wettest month (with the highest rainfall) is June (3.74").
The driest month (with the least rainfall) is January (0.94").
Average rainfall days in May
Williamson, IA
- Average rainfall days in May: 16.7 days
The month with the highest number of rainy days is May (16.7 days).
The month with the least rainy days is January (4.7 days).
Average snowfall in May
Williamson, IA
- Average snowfall in May: 0.28"
The month with the highest snowfall is February (4.13").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in May
Williamson, IA
- Average snowfall days in May: 0.3 days
The month with the highest number of snowfall days is January (10.2 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in May /
Average sunshine in May
Williamson, IA
- Average daylight in May: 14h and 30min
The month with the longest days is June (Average daylight: 15h and 6min).
The month with the shortest days is December (Average daylight: 9h and 18min).
- Average sunshine in May: 8h and 30min
The month with the most sunshine is July (Average sunshine: 10h and 12min).
The month with the least sunshine is January (Average sunshine: 4h and 12min).
Average sunshine days in May
Williamson, IA
- Average sunshine days in May: 11.5 days
The month with the most sunshine days is November (19.3 days).
The month with the least sunshine days is June (10.7 days).
Average UV index in May
Williamson, IA
- Average UV index in May: 5
The months with the highest UV index are June, July and August (UV index 6).
The month with the lowest UV index is January (UV index 1).
Average cloud cover in May
Williamson, IA
- Average cloud cover in May: 42
The month with the most cloud cover is January (Cloud cover 54).
The months with the least cloud cover are July and August (Cloud cover 30).
Average visibility in May
Williamson, IA
- Average visibility in May: 6mi
The months with the highest visibility are February, March, April, May, June, July, September, October, November and December (6mi).
The months with the lowest visibility are January and August (5mi).





