August weather forecast
Iona, SD

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Weather in August

The last month of the summer, August, is also a moderately hot month in Iona, South Dakota, with an average temperature ranging between max 85.8°F (29.9°C) and min 63.7°F (17.6°C).

Temperature

The transition into August marks the average high-temperature at a moderately hot 85.8°F (29.9°C), differing minimally from July's 88°F (31.1°C). Iona reports a sharp reduction in temperature during August, averaging at a comfortable 63.7°F (17.6°C) at night.

Heat index

The average heat index in August is evaluated at a hot 89.6°F (32°C). Persistent activity under exposure might lead to a feeling of weariness, with subsequent heat cramps.
Heat index evaluations are typically in the context of light winds and shaded environments. Exposure to the direct sun could elevate the heat index by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'apparent temperature' or 'felt air temperature', is a numerical representation of warmth when taking temperature and moisture levels into account. Additional elements including metabolic differences, the level of physical activity, and attire have a role in shaping the individual's temperature perception. It is important to note that direct sunlight can intensify the weather impact, potentially raising the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are highly critical for babies and toddlers. Youths are typically more endangered than adults since they usually sweat less. Their larger skin surface concerning their smaller bodies and higher heat production due to activity further adds to their vulnerability.

Humidity

In August, the average relative humidity is 59%.

Rainfall

In Iona, during August, the rain falls for 11 days and regularly aggregates up to 1.5" (38mm) of precipitation. Throughout the year, there are 107.6 rainfall days, and 17.83" (453mm) of precipitation is accumulated.

Snowfall

In Iona, snow does not fall in May through September.

Daylight

In August, the average length of the day is 13h and 55min.
On the first day of the month, sunrise is at 6:28 am and sunset at 8:59 pm. On the last day of August, sunrise is at 7:01 am and sunset at 8:14 pm CDT.

Sunshine

The average sunshine in August is 11h.

UV index

June through August, with an average maximum UV index of 6, are months with the highest UV index. A UV Index reading of 6 to 7 represents a high health risk from unprotected exposure to Sun's UV rays for average individuals.
Note: The maximum UV index of 6 during August translates into these guidelines:
Avert overexposure. Light-skinned people might experience burning in less than 20 minutes. Limit direct sun exposure especially between 10 a.m. and 4 p.m., when UV radiation is at its peak. However, keep in mind that shade structures may not provide full sun protection. Always opt for UVA and UVB-resistant sunglasses on radiant days.
Updated: Jun 24, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

Is it hot during August?

The average high-temperature and low-temperature during August are 85.8°F (29.9°C) and 63.7°F (17.6°C) respectively. In August, the average heat index (a.k.a. 'apparent temperature', 'feels like'), which factors the actual air temperature with the relative humidity, is evaluated at 89.6°F (32°C).

What is the average humidity in August in Iona?

In August, the average relative humidity is 59%.

How many days does it rain in August?

In Iona, in August, during 11 rainfall days, 1.5" (38mm) of precipitation is typically accumulated.

When it does not snow?

In Iona, snow does not fall in May through September.

What is the average length of the day in August?

In Iona, South Dakota, the average day length in August is 13h and 55min.

When are sunrise and sunset in August?

On the first day of August, sunrise is at 6:28 am and sunset at 8:59 pm. On the last day of the month, sunrise is at 7:01 am and sunset at 8:14 pm CDT.

How long on average sun shines in August?

In August, the average sunshine duration is 11h.

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.

How high is the UV index in August?

In Iona, the average daily maximum UV index in August is 6. A UV Index value of 6 to 7 symbolizes a high health threat from unsafe exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average snowfall
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in August
Iona, SD

Average temperature in August - Iona, SD
  • Average high temperature in August: 85.8°F

The warmest month (with the highest average high temperature) is July (88°F).
The month with the lowest average high temperature is January (26.1°F).

  • Average low temperature in August: 63.7°F

The month with the highest average low temperature is July (66.2°F).
The coldest month (with the lowest average low temperature) is January (12.6°F).

Average pressure in August
Iona, SD

Average pressure in August - Iona, SD
  • Average pressure in August: 29.91"Hg

The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.84"Hg).

Average wind speed in August
Iona, SD

Average wind speed in August - Iona, SD
  • Average wind speed in August: 9.1mph

The windiest month (with the highest average wind speed) is April (11.3mph).
The calmest month (with the lowest average wind speed) is August (9.1mph).

Average humidity in August
Iona, SD

Average humidity in August - Iona, SD
  • Average humidity in August: 59%

The month with the highest relative humidity is January (86%).
The month with the lowest relative humidity is September (58%).

Average rainfall in August
Iona, SD

Average rainfall in August - Iona, SD
  • Average rainfall in August: 1.5"

The wettest month (with the highest rainfall) is June (3.03").
The driest month (with the least rainfall) is November (0.55").

Average rainfall days in August
Iona, SD

Average rainfall days in August - Iona, SD
  • Average rainfall days in August: 11 days

The month with the highest number of rainy days is May (15.3 days).
The month with the least rainy days is February (3.3 days).

Average snowfall in August
Iona, SD

Average snowfall in August - Iona, SD
  • Average snowfall in August: 0"

The month with the highest snowfall is February (3.66").
The months with the least snowfall are May, June, July, August and September (0").

Average snowfall days in August
Iona, SD

Average snowfall days in August - Iona, SD
  • Average snowfall days in August: 0 days

The months with the highest number of snowfall days are January and February (11.7 days).
The months with the least snowfall days are June, July, August and September (0 days).

Average daylight in August /
Average sunshine in August
Iona, SD

Average daylight in August / Average sunshine in August - Iona, SD
  • Average daylight in August: 13h and 5min

The month with the longest days is June (Average daylight: 15h and 24min).
The month with the shortest days is December (Average daylight: 9h and 0min).

  • Average sunshine in August: 11h and 0min

The month with the most sunshine is July (Average sunshine: 11h and 24min).
The month with the least sunshine is January (Average sunshine: 4h and 42min).

Average sunshine days in August
Iona, SD

Average sunshine days in August - Iona, SD
  • Average sunshine days in August: 17.2 days

The month with the most sunshine days is November (20.7 days).
The month with the least sunshine days is April (11.8 days).

Average UV index in August
Iona, SD

Average UV index in August - Iona, SD
  • Average UV index in August: 6

The months with the highest UV index are June, July and August (UV index 6).
The month with the lowest UV index is February (UV index 1).

Average cloud cover in August
Iona, SD

Average cloud cover in August - Iona, SD
  • Average cloud cover in August: 20

The month with the most cloud cover is January (Cloud cover 49).
The month with the least cloud cover is August (Cloud cover 20).

Average visibility in August
Iona, SD

Average visibility in August - Iona, SD
  • Average visibility in August: 6mi

The months with the highest visibility are February, March, April, May, June, July, August, September, October, November and December (6mi).
The month with the lowest visibility is January (5mi).

Iona, South Dakota, USA

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