August weather forecast
Knoxville, IA

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Weather in August

August, the last month of the summer in Knoxville, is also a moderately hot month, with an average temperature fluctuating between 62.6°F (17°C) and 81.5°F (27.5°C).

Temperature

The advent of August observes an average high-temperature of a still warm 81.5°F (27.5°C), nearly identical to July's 82.8°F (28.2°C). Knoxville's August nights cool down to an average low-temperature of 62.6°F (17°C).

Heat index

In August, the heat index is computed to be a tropical 87.8°F (31°C). If exposure and activity persist, fatigue could ensue, possibly leading to heat cramps.
Metrics for the heat index primarily focus on shaded spots and light wind conditions. When exposed to the direct sun, the heat index may augment by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'real feel' or 'feels like', shows a temperature sensation when both heat and moisture conditions are combined. Metabolic differences, pregnancy status, and the level of physical activity are additional factors influencing an individual's weather perception. With direct sunlight, be aware that it might enhance the heat sensation, raising the heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are largely significant for babies and toddlers. Young individuals are typically more threatened than adults due to their reduced perspiration. Also, the larger skin surface proportionate to their small bodies and the increased heat from their activities magnify their risk.

Humidity

The average relative humidity in August is 79%.

Rainfall

In Knoxville, in August, during 11.5 rainfall days, 1.22" (31mm) of precipitation is typically accumulated. Throughout the year, there are 115.3 rainfall days, and 13.31" (338mm) of precipitation is accumulated.

Snowfall

June through September are months without snowfall.

Daylight

In August, the average length of the day in Knoxville is 13h and 47min.
On the first day of August, sunrise is at 6:08 am and sunset at 8:29 pm. On the last day of the month, sunrise is at 6:38 am and sunset at 7:46 pm CDT.

Sunshine

The average sunshine in August in Knoxville is 9.9h.

UV index

The months with the highest UV index in Knoxville are June through August, with an average maximum UV index of 6. A UV Index of 6 to 7 symbolizes a high health hazard from unprotected exposure to Sun's UV rays for the average person.
Note: A maximum UV index of 6 in August translates into the following recommendations:
Conform to measures and uphold sun safety traditions. Warding off skin and eye harm is necessary. Seek shade and minimize exposure to direct Sun in a period between 10 a.m. and 4 p.m. when UV radiation is most intense; keep in mind that shade structures like parasols or canopies do not provide perfect sun protection. Prioritize a wide-brim hat for comprehensive sun defense for your face, neck, eyes, and ears.
Updated: Feb 12, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the usual temperature for Knoxville in August?

The high-temperature, in August, in Knoxville, records 81.5°F (27.5°C), while the low-temperature is 62.6°F (17°C). In August, the average heat index (a.k.a. 'felt air temperature', 'feels like'), which combines relative humidity and air temperature, is computed to be 87.8°F (31°C).

What is the average humidity in August in Knoxville?

In Knoxville, the average relative humidity in August is 79%.

How much does it rain in Knoxville in August?

In Knoxville, in August, it is raining for 11.5 days, with typically 1.22" (31mm) of accumulated precipitation.

When it does not snow in Knoxville?

In Knoxville, Iowa, snow does not fall in June through September.

What is the average length of the day in August in Knoxville?

In Knoxville, Iowa, the average day length in August is 13h and 47min.

When is the sunrise / sunset in August in Knoxville?

On the first day of August, sunrise is at 6:08 am and sunset at 8:29 pm. On the last day of the month, sunrise is at 6:38 am and sunset at 7:46 pm CDT.

How long on average sun shines in August in Knoxville?

In Knoxville, the average sunshine duration in August is 9.9h.

What are the months with the highest UV index in Knoxville?

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

What is the UV index intensity in August in Knoxville?

In Knoxville, the average daily maximum UV index in August is 6. A UV Index estimate of 6 to 7 represents a high health risk from unprotected exposure to UV radiation.
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
Knoxville, IA

Average temperature in August - Knoxville, IA
  • Average high temperature in August: 81.5°F

The warmest month (with the highest average high temperature) is July (82.8°F).
The month with the lowest average high temperature is January (28.6°F).

  • Average low temperature in August: 62.6°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 (15.1°F).

Average pressure in August
Knoxville, IA

Average pressure in August - Knoxville, IA
  • Average pressure in August: 29.97"Hg

The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.89"Hg).

Average wind speed in August
Knoxville, IA

Average wind speed in August - Knoxville, IA
  • Average wind speed in August: 6.8mph

The windiest month (with the highest average wind speed) is January (10.5mph).
The calmest month (with the lowest average wind speed) is August (6.8mph).

Average humidity in August
Knoxville, IA

Average humidity in August - Knoxville, IA
  • Average humidity in August: 79%

The month with the highest relative humidity is January (83%).
The month with the lowest relative humidity is October (71%).

Average rainfall in August
Knoxville, IA

Average rainfall in August - Knoxville, IA
  • Average rainfall in August: 1.22"

The wettest month (with the highest rainfall) is May (2.24").
The driest months (with the least rainfall) are February and December (0.47").

Average rainfall days in August
Knoxville, IA

Average rainfall days in August - Knoxville, IA
  • Average rainfall days in August: 11.5 days

The month with the highest number of rainy days is May (15.3 days).
The month with the least rainy days is February (3.9 days).

Average snowfall in August
Knoxville, IA

Average snowfall in August - Knoxville, IA
  • Average snowfall in August: 0"

The month with the highest snowfall is January (2.24").
The months with the least snowfall are June, July, August and September (0").

Average snowfall days in August
Knoxville, IA

Average snowfall days in August - Knoxville, IA
  • Average snowfall days in August: 0 days

The month with the highest number of snowfall days is January (8.7 days).
The months with the least snowfall days are June, July, August and September (0 days).

Average daylight in August /
Average sunshine in August
Knoxville, IA

Average daylight in August / Average sunshine in August - Knoxville, IA
  • Average daylight in August: 13h and 5min

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 August: 9h and 5min

The month with the most sunshine is July (Average sunshine: 10h and 30min).
The month with the least sunshine is January (Average sunshine: 4h and 18min).

Average sunshine days in August
Knoxville, IA

Average sunshine days in August - Knoxville, IA
  • Average sunshine days in August: 16.3 days

The months with the most sunshine days are November and December (20.5 days).
The month with the least sunshine days is June (11.6 days).

Average UV index in August
Knoxville, IA

Average UV index in August - Knoxville, IA
  • 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 January (UV index 1).

Average cloud cover in August
Knoxville, IA

Average cloud cover in August - Knoxville, IA
  • Average cloud cover in August: 29

The month with the most cloud cover is January (Cloud cover 53).
The months with the least cloud cover are July, August and September (Cloud cover 29).

Average visibility in August
Knoxville, IA

Average visibility in August - Knoxville, IA
  • Average visibility in August: 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).

Knoxville, Iowa, USA

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