May weather forecast
River Sioux, IA

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Weather in May

May, the last month of the spring in River Sioux, is a pleasant month, with temperature in the range of an average low of 53.2°F (11.8°C) and an average high of 70.7°F (21.5°C).

Temperature

The onset of May brings a rise in the average high-temperature, elevating from a refreshing 59.9°F (15.5°C) in April to an agreeable 70.7°F (21.5°C). An average low-temperature of 53.2°F (11.8°C) is recorded during the nights in May in River Sioux.

Humidity

The average relative humidity in May in River Sioux is 71%.

Rainfall

The month with the most rainfall is May, when the rain falls for 16.3 days and typically aggregates up to 3.5" (89mm) of precipitation.

Snowfall

Months with snowfall in River Sioux are January through May, October through December. May is the last month it regularly snows. During 0.2 snowfall days, in May, River Sioux aggregates 0.08" (2mm) of snow. In River Sioux, during the entire year, snow falls for 32.8 days and aggregates up to 11.97" (304mm) of snow.

Daylight

In May, the average length of the day is 14h and 34min.
On the first day of May, sunrise is at 6:19 am and sunset at 8:23 pm. On the last day of the month, sunrise is at 5:51 am and sunset at 8:52 pm CDT.

Sunshine

The average sunshine in May in River Sioux, Iowa, is 9.1h.

UV index

The average daily maximum UV index in May in River Sioux is 5. A UV Index value of 3 to 5 symbolizes a moderate threat to health from unprotected exposure to Sun's UV rays for average individuals.
Note: A maximum daily UV index of 5 during May morphs into the following directions:
Act with care - The need to guard against sun damage is communicated. Avoiding direct sun during mid-day hours can prevent harmful UV radiation exposure. A hat with a broad brim is indispensable, filtering out up to half of UV rays. Be informed! The Sun's UV radiation can be nearly doubled due to the reflection from snow.
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Frequently asked questions

What are May temperatures in River Sioux?

May temperatures vary between a high-temperature of 70.7°F (21.5°C) and a low-temperature of 53.2°F (11.8°C).

What is the average humidity in May in River Sioux?

In River Sioux, Iowa, the average relative humidity in May is 71%.

What is the wettest month in River Sioux?

May is the month with the most rainfall in River Sioux. Rain falls for 16.3 days and accumulates 3.5" (89mm) of precipitation.

How much does it rain in River Sioux in May?

In May, the rain falls for 16.3 days. Throughout May, 3.5" (89mm) of precipitation is accumulated.

What is the last month it snows in River Sioux?

May is the last month it regularly snows. During 0.2 snowfall days, in May, River Sioux aggregates 0.08" (2mm) of snow.

How many hours of daylight does River Sioux have in May?

In May, the average day length in River Sioux is 14h and 34min.

When are sunrise and sunset in May in River Sioux?

In May, on the first day of the month, sunrise is at 6:19 am and sunset at 8:23 pm. On the last day of the month, sunrise is at 5:51 am and sunset at 8:52 pm CDT.

How many hours of sunshine does River Sioux have in May?

The average sunshine duration in May in River Sioux, Iowa, is 9.1h.

What is the UV index reading in May in River Sioux?

The average daily maximum UV index in May is 5. A UV Index value of 3 to 5 symbolizes a moderate vulnerability from exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in May
River Sioux, IA

Average temperature in May - River Sioux, IA
  • Average high temperature in May: 70.7°F

The warmest month (with the highest average high temperature) is July (84.4°F).
The month with the lowest average high temperature is January (28.8°F).

  • Average low temperature in May: 53.2°F

The month with the highest average low temperature is July (65.5°F).
The coldest month (with the lowest average low temperature) is January (15.3°F).

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Average pressure in May
River Sioux, IA

Average pressure in May - River Sioux, IA
  • Average pressure in May: 29.92"Hg

The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.86"Hg).

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Average wind speed in May
River Sioux, IA

Average wind speed in May - River Sioux, IA
  • Average wind speed in May: 9.2mph

The windiest month (with the highest average wind speed) is April (10.8mph).
The calmest month (with the lowest average wind speed) is July (7.2mph).

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Average humidity in May
River Sioux, IA

Average humidity in May - River Sioux, IA
  • Average humidity in May: 71%

The month with the highest relative humidity is January (81%).
The month with the lowest relative humidity is October (66%).

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Average rainfall in May
River Sioux, IA

Average rainfall in May - River Sioux, IA
  • Average rainfall in May: 3.5"

The wettest month (with the highest rainfall) is May (3.5").
The driest month (with the least rainfall) is January (0.71").

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Average rainfall days in May
River Sioux, IA

Average rainfall days in May - River Sioux, IA
  • Average rainfall days in May: 16.3 days

The month with the highest number of rainy days is June (16.8 days).
The month with the least rainy days is February (3.3 days).

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Average snowfall in May
River Sioux, IA

Average snowfall in May - River Sioux, IA
  • Average snowfall in May: 0.08"

The month with the highest snowfall is January (2.8").
The months with the least snowfall are June, July, August and September (0").

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Average snowfall days in May
River Sioux, IA

Average snowfall days in May - River Sioux, IA
  • Average snowfall days in May: 0.2 days

The month with the highest number of snowfall days is January (9.4 days).
The months with the least snowfall days are June, July, August and September (0 days).

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Average daylight in May /
Average sunshine in May
River Sioux, IA

Average daylight in May / Average sunshine in May - River Sioux, 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: 9h and 1min

The month with the most sunshine is July (Average sunshine: 10h and 42min).
The month with the least sunshine is January (Average sunshine: 4h and 42min).

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Average sunshine days in May
River Sioux, IA

Average sunshine days in May - River Sioux, IA
  • Average sunshine days in May: 12.3 days

The month with the most sunshine days is November (20.7 days).
The month with the least sunshine days is June (11.3 days).

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Average UV index in May
River Sioux, IA

Average UV index in May - River Sioux, IA
  • Average UV index in May: 5

The months with the highest UV index are June, July and August (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 2).

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Average cloud cover in May
River Sioux, IA

Average cloud cover in May - River Sioux, IA
  • Average cloud cover in May: 38

The month with the most cloud cover is January (Cloud cover 49).
The month with the least cloud cover is July (Cloud cover 25).

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Average visibility in May
River Sioux, IA

Average visibility in May - River Sioux, IA
  • 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).

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River Sioux, Iowa, USA

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