May weather forecastDerby, IA
May
Weather in May
The last month of the spring, May, is an agreeable month in Derby, Iowa, with temperature in the range of an average high of 69.4°F (20.8°C) and an average low of 52.7°F (11.5°C).Temperature
With the arrival of May, the average high-temperature transitions from a mild 60.1°F (15.6°C) in April to an agreeable 69.4°F (20.8°C). Derby throughout May, records an average low-temperature of 52.7°F (11.5°C).Humidity
The average relative humidity in May is 81%.Rainfall
In May, the rain falls for 16.7 days. Throughout May, 3.7" (94mm) of precipitation is accumulated. Throughout the year, there are 131.1 rainfall days, and 25.71" (653mm) of precipitation is accumulated.Snowfall
January through May, October through December are months with snowfall. May is the last month it regularly snows. During 0.3 snowfall days, in May, Derby aggregates 0.28" (7mm) of snow. In Derby, during the entire year, snow falls for 33.4 days and aggregates up to 13.54" (344mm) of snow.Daylight
In Derby, the average length of the day in May is 14h and 29min.On the first day of May in Derby, Iowa, sunrise is at 6:10 am and sunset at 8:10 pm. On the last day of the month, sunrise is at 5:44 am and sunset at 8:39 pm CDT.
Sunshine
In May, the average sunshine in Derby is 8.5h.UV index
In May, the average daily maximum UV index is 5. A UV Index of 3 to 5 symbolizes a moderate threat to health from unprotected exposure to Sun's UV rays for average individuals.Note: An average maximum UV index of 5 in May leads to these recommendations:
Take precautions. Light skin individuals may get burned in less than 30 minutes. Midday is the peak time for the Sun's radiation; stay in the shade and protect yourself. By wearing a generously brimmed hat, you can cut UV radiation exposure significantly. Beware! The strength of the UV rays is increased nearly double-fold by the reflection of the snow.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in May
Derby, 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
Derby, 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
Derby, 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
Derby, 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
Derby, 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
Derby, 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
Derby, 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
Derby, 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
Derby, 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
Derby, 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
Derby, 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
Derby, 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
Derby, 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).
