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
May brings a rise in the average high-temperature, transitioning from April's enjoyable 60.8°F (16°C) to an agreeable 70.9°F (21.6°C). Throughout May, Merrimac records an average temperature of 53.8°F (12.1°C) at night.Humidity
In Merrimac, the average relative humidity in May is 79%.Rainfall
The month with the most rainfall is May, when the rain falls for 18.3 days and typically aggregates up to 4.29" (109mm) of precipitation.Snowfall
May through September are months without snowfall.Daylight
The average length of the day in May is 14h and 30min.On the first day of May, sunrise is at 6:03 am and sunset at 8:04 pm. On the last day of the month, sunrise is at 5:36 am and sunset at 8:32 pm CDT.
Sunshine
In Merrimac, the average sunshine in May is 8.6h.UV index
In May, the average daily maximum UV index is 5. A UV Index reading of 3 to 5 represents a moderate health risk from unsafe exposure to UV radiation for the ordinary person.Note: During May, 5 as the daily maximum UV index converts into the following advice:
Act with care - The need to guard against sun damage is communicated. Sun exposure should be minimized, especially during midday, to avoid harmful UV radiation. Sunglasses providing both UVA and UVB protection are non-negotiable on sunlit days.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What are May temperatures?
What is the average humidity in May?
What is the rainiest month?
How much does it rain in May?
When it does not snow?
Does it snow in May?
What is the average length of the day in May?
When is the sunrise / sunset in May?
How many hours of sunshine does Merrimac have in May?
How high is the UV index in May?
Average temperature in May
Merrimac, IA
- Average high temperature in May: 70.9°F
The warmest month (with the highest average high temperature) is July (82.4°F).
The month with the lowest average high temperature is January (29.7°F).
- Average low temperature in May: 53.8°F
The month with the highest average low temperature is July (65.3°F).
The coldest month (with the lowest average low temperature) is January (17.4°F).
Average pressure in May
Merrimac, IA
- Average pressure in May: 29.94"Hg
The month with the highest atmospheric pressure is January (30.15"Hg).
The month with the lowest atmospheric pressure is June (29.9"Hg).
Average wind speed in May
Merrimac, 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 (6.9mph).
Average humidity in May
Merrimac, IA
- Average humidity in May: 79%
The month with the highest relative humidity is July (83%).
The month with the lowest relative humidity is October (71%).
Average rainfall in May
Merrimac, IA
- Average rainfall in May: 4.29"
The wettest month (with the highest rainfall) is May (4.29").
The driest months (with the least rainfall) are February and December (1.38").
Average rainfall days in May
Merrimac, IA
- Average rainfall days in May: 18.3 days
The month with the highest number of rainy days is May (18.3 days).
The month with the least rainy days is February (4.6 days).
Average snowfall in May
Merrimac, IA
- Average snowfall in May: 0"
The month with the highest snowfall is January (4.76").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in May
Merrimac, IA
- Average snowfall days in May: 0 days
The month with the highest number of snowfall days is January (9.6 days).
The months with the least snowfall days are May, June, July, August and September (0 days).
Average daylight in May /
Average sunshine in May
Merrimac, IA
- Average daylight in May: 14h and 3min
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 4min
The month with the most sunshine is July (Average sunshine: 10h and 0min).
The month with the least sunshine is January (Average sunshine: 4h and 0min).
Average sunshine days in May
Merrimac, IA
- Average sunshine days in May: 10.6 days
The month with the most sunshine days is October (18.4 days).
The month with the least sunshine days is May (10.6 days).
Average UV index in May
Merrimac, 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
Merrimac, IA
- Average cloud cover in May: 42
The month with the most cloud cover is January (Cloud cover 56).
The months with the least cloud cover are July, August and September (Cloud cover 31).
Average visibility in May
Merrimac, IA
- Average visibility in May: 6mi
The months with the highest visibility are January, February, March, April, May, June, August, September, October, November and December (6mi).
The month with the lowest visibility is July (5mi).
Merrimac, Iowa, USA
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