August weather forecast
Griggsville, IL

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Weather in August

The last month of the summer, August, is also a moderately hot month in Griggsville, Illinois, with an average temperature ranging between max 83.5°F (28.6°C) and min 65.5°F (18.6°C).

Temperature

Griggsville experiences a subtle adjustment in high-temperatures to a still moderately hot 83.5°F (28.6°C) with the onset of August, maintaining near parity with July's 84.4°F (29.1°C). Griggsville, during August, witnesses an average low-temperature of 65.5°F (18.6°C).

Heat index

The heat index for August is calculated to be a hot 91.4°F (33°C). Adopt extra safety steps, risk of heat exhaustion and heat cramps is notable. Sustained activity might cause heatstroke.
Factoring in the heat index, values are geared towards shaded areas with light breezes. If directly exposed to the sun, the heat index could rise by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'felt air temperature' or 'feels like', is a metric representing the sensation of warmth when air temperature and moisture come together. The impact of temperature is individual, as people's perception of weather may change based on their body mass, height, and physical activity. One must note that being under the direct sun can escalate the heat's effects, with the heat index possibly rising by 15 Fahrenheit (8 Celsius) degrees. Heat index values hold particular significance for children. Children usually face more risks than adults as their ability to sweat is less. Additionally, their larger skin surface in relation to their petite bodies and higher heat output due to their activities increases their vulnerability.

Humidity

The average relative humidity in August is 78%.

Rainfall

In Griggsville, in August, it is raining for 12.4 days, with typically 1.85" (47mm) of accumulated precipitation. In Griggsville, during the entire year, the rain falls for 128.8 days and collects up to 18.35" (466mm) of precipitation.

Snowfall

May through October are months without snowfall.

Daylight

In Griggsville, the average length of the day in August is 13h and 41min.
On the first day of August, sunrise is at 6:02 am and sunset at 8:15 pm. On the last day of the month, sunrise is at 6:30 am and sunset at 7:35 pm CDT.

Sunshine

In August, the average sunshine is 10h.

UV index

The months with the highest UV index are June through August, with an average maximum UV index of 6. A UV Index estimate of 6 to 7 represents a high health vulnerability from exposure to the Sun's UV rays for the average person.
Note: The UV index of 6 during August leads to these advisories:
Beware of overexposure. Fair-skinned individuals risk burning in less than 20 minutes. The Sun's UV radiation is at its strongest between the hours of 10 a.m. and 4 p.m. Minimize direct exposure to the sun during this period. A wide-brimmed hat provides unparalleled sun protection for sensitive areas like the eyes, ears, and neck.
Updated: Jul 25, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

How hot is it in August?

The average high-temperature and low-temperature in Griggsville during August are 83.5°F (28.6°C) and 65.5°F (18.6°C) respectively. The average heat index (a.k.a. 'real feel', 'feels like'), which represents the influence of relative humidity on air temperature, in August is calculated to be 91.4°F (33°C).

What is the average humidity in August?

The average relative humidity in August is 78%.

How many days does it rain in August?

In Griggsville, in August, it is raining for 12.4 days, with typically 1.85" (47mm) of accumulated precipitation.

When it does not snow?

May through October are months without snowfall.

What is the average length of the day in August?

In Griggsville, the average day length in August is 13h and 41min.

When are sunrise and sunset in August?

On the first day of August, sunrise is at 6:02 am and sunset at 8:15 pm. On the last day of the month, sunrise is at 6:30 am and sunset at 7:35 pm CDT.

How long on average sun shines in August?

In August, the average sunshine duration is 10h.

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 is the UV index reading in August?

In Griggsville, the average daily maximum UV index in August is 6. A UV Index value of 6 to 7 symbolizes a high hazard to health from exposure to the Sun's 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
Griggsville, IL

Average temperature in August - Griggsville, IL
  • Average high temperature in August: 83.5°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 (33.8°F).

  • Average low temperature in August: 65.5°F

The month with the highest average low temperature is July (66.7°F).
The coldest month (with the lowest average low temperature) is January (21.6°F).

Average pressure in August
Griggsville, IL

Average pressure in August - Griggsville, IL
  • Average pressure in August: 29.97"Hg

The month with the highest atmospheric pressure is January (30.15"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).

Average wind speed in August
Griggsville, IL

Average wind speed in August - Griggsville, IL
  • Average wind speed in August: 6.2mph

The windiest months (with the highest average wind speed) are January, February and April (9.8mph).
The calmest month (with the lowest average wind speed) is July (6mph).

Average humidity in August
Griggsville, IL

Average humidity in August - Griggsville, IL
  • Average humidity in August: 78%

The months with the highest relative humidity are June and July (81%).
The month with the lowest relative humidity is October (71%).

Average rainfall in August
Griggsville, IL

Average rainfall in August - Griggsville, IL
  • Average rainfall in August: 1.85"

The wettest month (with the highest rainfall) is May (2.44").
The driest month (with the least rainfall) is February (0.75").

Average rainfall days in August
Griggsville, IL

Average rainfall days in August - Griggsville, IL
  • Average rainfall days in August: 12.4 days

The month with the highest number of rainy days is May (16.8 days).
The month with the least rainy days is January (4.5 days).

Average snowfall in August
Griggsville, IL

Average snowfall in August - Griggsville, IL
  • Average snowfall in August: 0"

The month with the highest snowfall is January (2.05").
The months with the least snowfall are May, June, July, August, September and October (0").

Average snowfall days in August
Griggsville, IL

Average snowfall days in August - Griggsville, IL
  • Average snowfall days in August: 0 days

The month with the highest number of snowfall days is January (6.3 days).
The months with the least snowfall days are May, June, July, August and September (0 days).

Average daylight in August /
Average sunshine in August
Griggsville, IL

Average daylight in August / Average sunshine in August - Griggsville, IL
  • Average daylight in August: 13h and 4min

The month with the longest days is June (Average daylight: 14h and 54min).
The month with the shortest days is December (Average daylight: 9h and 24min).

  • Average sunshine in August: 10h and 0min

The months with the most sunshine are June and July (Average sunshine: 10h and 18min).
The month with the least sunshine is January (Average sunshine: 4h and 24min).

Average sunshine days in August
Griggsville, IL

Average sunshine days in August - Griggsville, IL
  • Average sunshine days in August: 16.4 days

The month with the most sunshine days is December (20.7 days).
The month with the least sunshine days is June (12.3 days).

Average UV index in August
Griggsville, IL

Average UV index in August - Griggsville, IL
  • Average UV index in August: 6

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 cloud cover in August
Griggsville, IL

Average cloud cover in August - Griggsville, IL
  • Average cloud cover in August: 29

The month with the most cloud cover is January (Cloud cover 52).
The months with the least cloud cover are June, July, August and September (Cloud cover 29).

Average visibility in August
Griggsville, IL

Average visibility in August - Griggsville, IL
  • 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).

Griggsville, Illinois, USA

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