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
Herndon sees an increase in average high-temperatures during May, moving from a mild 58.5°F (14.7°C) in April to a pleasant 69.4°F (20.8°C). An average low-temperature of 53.1°F (11.7°C) is expected during May.Humidity
In May, the average relative humidity in Herndon is 74%.Rainfall
The month with the most rainfall is May, when the rain falls for 16.2 days and typically aggregates up to 4.06" (103mm) of precipitation.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, Herndon aggregates 0.12" (3mm) of snow. In Herndon, during the entire year, snow falls for 38.1 days and aggregates up to 15.31" (389mm) of snow.Daylight
The average length of the day in May in Herndon is 14h and 34min.On the first day of May, sunrise is at 6:12 am and sunset at 8:16 pm. On the last day of the month, sunrise is at 5:44 am and sunset at 8:45 pm CDT.
Sunshine
In May, the average sunshine is 8.6h.UV index
In May, the average daily maximum UV index is 5. A UV Index value of 3 to 5 symbolizes a medium health hazard from unprotected exposure to Sun's UV rays for average individuals.Note: A maximum UV index of 5 in May translates into the following recommendations:
Ensure safety - Recommendations to avert sunburn are presented. Solar radiation peaks around mid-day, so it's wise to limit exposure to the Sun at this time. A hat with a generous brim can prevent nearly 50% of UV rays from reaching your eyes. Be attentive! The reflective property of snow can nearly double the Sun's UV radiation.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the average May temperature?
What is the average humidity in May in Herndon?
What is the rainiest month?
How much does it rain in May?
What is the last month it snows?
What is the average length of the day in May?
What time are sunrise and sunset in May in Herndon?
How many hours of sunshine does Herndon have in May?
What is the UV index intensity in May?
Average temperature in May
Herndon, IA
- Average high temperature in May: 69.4°F
The warmest month (with the highest average high temperature) is July (82°F).
The month with the lowest average high temperature is January (26.8°F).
- Average low temperature in May: 53.1°F
The month with the highest average low temperature is July (64.6°F).
The coldest month (with the lowest average low temperature) is January (13.5°F).
Average pressure in May
Herndon, 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 (29.88"Hg).
Average wind speed in May
Herndon, IA
- Average wind speed in May: 9.1mph
The windiest month (with the highest average wind speed) is April (10.7mph).
The calmest months (with the lowest average wind speed) are July and August (7.1mph).
Average humidity in May
Herndon, IA
- Average humidity in May: 74%
The month with the highest relative humidity is January (84%).
The month with the lowest relative humidity is October (69%).
Average rainfall in May
Herndon, IA
- Average rainfall in May: 4.06"
The wettest month (with the highest rainfall) is May (4.06").
The driest month (with the least rainfall) is January (0.87").
Average rainfall days in May
Herndon, IA
- Average rainfall days in May: 16.2 days
The month with the highest number of rainy days is June (17.3 days).
The month with the least rainy days is February (3.4 days).
Average snowfall in May
Herndon, IA
- Average snowfall in May: 0.12"
The month with the highest snowfall is January (4.29").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in May
Herndon, IA
- Average snowfall days in May: 0.3 days
The month with the highest number of snowfall days is January (9.8 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in May /
Average sunshine in May
Herndon, IA
- 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 July (Average sunshine: 10h and 12min).
The month with the least sunshine is January (Average sunshine: 4h and 12min).
Average sunshine days in May
Herndon, IA
- Average sunshine days in May: 13.3 days
The month with the most sunshine days is November (19.4 days).
The month with the least sunshine days is June (11.1 days).
Average UV index in May
Herndon, IA
- Average UV index in May: 5
The months with the highest UV index are June and July (UV index 6).
The months with the lowest UV index are January, February, October, November and December (UV index 2).
Average cloud cover in May
Herndon, IA
- Average cloud cover in May: 42
The month with the most cloud cover is January (Cloud cover 55).
The months with the least cloud cover are July and September (Cloud cover 30).
Average visibility in May
Herndon, IA
- Average visibility in May: 6mi
The months with the highest visibility are February, March, April, May, June, September, October, November and December (6mi).
The months with the lowest visibility are January, July and August (5mi).
Herndon, Iowa, USA
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