Climate and monthly weather forecast
River Sioux, IA

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Weather in January

January, like December, is another subzero cold winter month in River Sioux, Iowa, with an average temperature ranging between max 28.8°F (-1.8°C) and min 15.3°F (-9.3°C). January, having an average high-temperature of 28.8°F (-1.8°C) and an average low-temperature of 15.3°F (-9.3°C), is the coldest month. Weather in January »

Weather in February

The last month of the winter, February, is a cold month in River Sioux, Iowa, with an average temperature varying between 32.7°F (0.4°C) and 18.7°F (-7.4°C). With the onset of February, River Sioux's average high-temperature clocks in at a wintry 32.7°F (0.4°C), showing a minor fluctuation from the previous month. Weather in February »

Weather in March

The first month of the spring, March, is a chilly month in River Sioux, Iowa, with an average temperature fluctuating between 48.7°F (9.3°C) and 32.7°F (0.4°C). River Sioux's weather experiences a significant temperature rise with the arrival of March, soaring from an icy 32.7°F (0.4°C) in February to a chilly 48.7°F (9.3°C). Weather in March »

Weather in April

April is a mild spring month in River Sioux, Iowa, with an average temperature varying between 42.4°F (5.8°C) and 59.9°F (15.5°C). April's arrival signals a temperature shift, moving from a frosty 48.7°F (9.3°C) in March to a moderate 59.9°F (15.5°C). Weather in April »

Weather in May

The last month of the spring, May, is a pleasant month in River Sioux, Iowa, with an average temperature ranging between max 70.7°F (21.5°C) and min 53.2°F (11.8°C). May brings a rise in the average high-temperature, transitioning from April's refreshing 59.9°F (15.5°C) to an agreeable 70.7°F (21.5°C). Weather in May »

Weather in June

The first month of the summer, June, is a moderately hot month in River Sioux, Iowa, with temperature in the range of an average high of 80.8°F (27.1°C) and an average low of 63.7°F (17.6°C). As June arrives, River Sioux's weather shows an increase in high-temperatures, moving from May's pleasant 70.7°F (21.5°C) to a warm 80.8°F (27.1°C). Weather in June »

Weather in July

July, like June, in River Sioux, Iowa, is another warm summer month, with temperature in the range of an average low of 65.5°F (18.6°C) and an average high of 84.4°F (29.1°C). The month of July sees the highest average temperatures, reaching 84.4°F (29.1°C) at the peak and 65.5°F (18.6°C) at the low. The average heat index in July is estimated at a hot 93.2°F (34°C). Weather in July »

Weather in August

August, the last month of the summer in River Sioux, is another warm month, with an average temperature fluctuating between 62.2°F (16.8°C) and 82.2°F (27.9°C). The average high-temperature during August registers at a still warm 82.2°F (27.9°C), maintaining a close resemblance to the previous month. Weather in August »

Weather in September

The first month of the autumn, September, is also a moderately hot month in River Sioux, Iowa, with an average temperature fluctuating between 56.3°F (13.5°C) and 76.5°F (24.7°C). During the shift to September, River Sioux records a mild decrease in average high-temperature, moving from 82.2°F (27.9°C) in August to a still warm 76.5°F (24.7°C). Weather in September »

Weather in October

October, the same as September, is another comfortable autumn month in River Sioux, Iowa, with an average temperature fluctuating between 61°F (16.1°C) and 44.6°F (7°C). The drop of average high-temperatures is noticeable in October, with a decrease from a moderately hot 76.5°F (24.7°C) in September to a refreshing 61°F (16.1°C). Weather in October »

Weather in November

The last month of the autumn, November, is another chilly month in River Sioux, Iowa, with an average temperature varying between 32.9°F (0.5°C) and 47.5°F (8.6°C). River Sioux experiences a temperature shift at the start of November, with average high-temperatures adjusting from a comfortable 61°F (16.1°C) in October to a frosty 47.5°F (8.6°C). Weather in November »

Weather in December

The first month of the winter, December, is also an icy month in River Sioux, Iowa, with an average temperature fluctuating between 21°F (-6.1°C) and 32.9°F (0.5°C). River Sioux in December experiences a marked decrease in the average high-temperature, descending from November's chilly 47.5°F (8.6°C) to a wintry 32.9°F (0.5°C). Weather in December »
Updated: Jul 19, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What month is the coldest?

January, with its high-temperature average of 28.8°F (-1.8°C) and a low-temperature average of 15.3°F (-9.3°C), is the coldest month.

What is the most humid month in River Sioux?

With an average relative humidity of 81%, January is the most humid month.

What is the driest month?

January is the month with the least rainfall. Rain falls for 4.3 days and accumulates 0.71" (18mm) of precipitation.

How many days does it rain in River Sioux?

In River Sioux, during the entire year, the rain falls for 125.1 days and collects up to 22.64" (575mm) of precipitation.

When does it snow?

Months with snowfall are January through May, October through December.

What is the snowiest month?

January is the month with the most snowfall in River Sioux. Snow falls for 9.4 days and accumulates 2.8" (71mm) of snow.

How much does it snow?

In River Sioux, during the entire year, snow falls for 32.8 days and aggregates up to 11.97" (304mm) of snow.

What is the month with the least sunshine?

January has the least sunshine of the year, with an average of 4.7h of sunshine.

What is the month with the lowest UV index?

The months with the lowest UV index are January, February, November and December, with an average maximum UV index of 2.

When is Daylight Saving Time (DST) in River Sioux?

On Sunday, March 10. 2024, at 2:00 am, Daylight Saving Time starts, and the time zone changes from CST to CDT. Daylight Saving Time ends Sunday, November 3. 2024, at 2:00 am, and the time zone reverts from CDT to CST.

What is the rainiest month?

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.

When it does not snow?

In River Sioux, snow does not fall in June through September.

When are the longest days?

With an average of 15h and 12min of daylight, June has the longest days of the year.

What are the months with the highest UV index?

June through August, with an average maximum UV index of 6, are months with the highest UV index.

What month is the hottest?

River Sioux's warmest weather arrives in July, when temperatures average a high of 84.4°F (29.1°C) and a low of 65.5°F (18.6°C).

What month has the most sunshine?

July has the most sunshine of the year, with an average of 10.7h of sunshine.

What is the least humid month?

October is the least humid month, with an average relative humidity of 66%.

What is the month with the shortest days?

December has the shortest days of the year, with an average of 9h and 12min of daylight.

Average temperature
River Sioux, IA

Average temperature - River Sioux, IA

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).

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).

Average pressure
River Sioux, IA

Average pressure - River Sioux, IA

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

Average wind speed
River Sioux, IA

Average wind speed - River Sioux, IA

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).

Average humidity
River Sioux, IA

Average humidity - River Sioux, IA

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

Average rainfall
River Sioux, IA

Average rainfall - River Sioux, IA

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

Average rainfall days
River Sioux, IA

Average rainfall days - River Sioux, IA

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).

Average snowfall
River Sioux, IA

Average snowfall - River Sioux, IA

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

Average snowfall days
River Sioux, IA

Average snowfall days - River Sioux, IA

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).

Average daylight / Average sunshine
River Sioux, IA

Average daylight / Average sunshine - River Sioux, IA

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).

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).

Average sunshine days
River Sioux, IA

Average sunshine days - River Sioux, IA

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

Average UV index
River Sioux, IA

Average UV index - River Sioux, IA

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).

Average visibility
River Sioux, IA

Average visibility - River Sioux, IA

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).

River Sioux, Iowa, USA

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