August weather forecast
Guerneville, CA

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Weather in August

The last month of the summer, August, is also a moderately hot month in Guerneville, California, with an average temperature varying between 81°F (27.2°C) and 53.4°F (11.9°C).

Temperature

In Guerneville, California, August is the month with the highest recorded average temperatures, measuring a high of 81°F (27.2°C) and a low of 53.4°F (11.9°C).

Heat index

For most parts of August, the heat index is computed to be 84.2°F (29°C). Persistently participating in activities during exposure may lead to fatigue and induce heat cramps.
Data suggests that the heat index is set for environments in shade and with a light wind. Facing direct sunlight may hike up the heat index by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'felt air temperature' or 'apparent temperature', is a calculated temperature value of how hot it feels when the moisture in the air is factored in. The effect is personal, with varied weather perceptions among individuals due to differences in body mass, stature, and physical activity. Direct exposure to sun rays can potentially augment the heat sensation, elevating the heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are primarily vital for children. Children often miss understanding the importance of rest and rehydration. Thirst usually appears late during dehydration - therefore, maintaining hydration, particularly during long physical activities, is essential.

Humidity

In Guerneville, the average relative humidity in August is 66%.

Rainfall

July and August are months with the least rain when the rain falls for 0.9 days and typically aggregates up to 0.04" (1mm) of rain.

Daylight

In August, the average length of the day is 13h and 37min.
On the first day of August, sunrise is at 6:14 am and sunset at 8:21 pm. On the last day of the month, sunrise is at 6:41 am and sunset at 7:42 pm PDT.

Sunshine

In Guerneville, the average sunshine in August is 11.7h.

UV index

June through August, with an average maximum UV index of 6, are months with the highest UV index in Guerneville, California. A UV Index value of 6 to 7 symbolizes a high health hazard from exposure to the Sun's UV radiation for the ordinary person.
Note: The maximum daily UV index of 6 in August interprets into the following recommendations:
Ward off overexposure. Defence against solar harm is crucial. Stay in the shade and limit direct sun exposure between 10 a.m. and 4 p.m., when UV radiation is at its strongest. Remember, however, that not all shade structures provide full sun protection. For holistic sun protection encompassing the eyes, ears, face, and neck, a wide-brim hat is key.
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Frequently asked questions

What month is the hottest in Guerneville?

The warmest time of the year in Guerneville is August, with temperatures averaging a high of 81°F (27.2°C) and a low of 53.4°F (11.9°C).

What is the temperature in August in Guerneville?

In Guerneville, in August, the average high-temperature is 81°F (27.2°C), and the average low-temperature is 53.4°F (11.9°C). The average heat index (a.k.a. 'feels like', 'felt air temperature'), which calculates the temperature value influenced by the moisture in the air, in August is computed to be 84.2°F (29°C).

What is the average humidity in August in Guerneville?

In Guerneville, the average relative humidity in August is 66%.

What is the driest month in Guerneville?

July and August are months with the least rain in Guerneville, California, when the rain falls for 0.9 days and typically aggregates up to 0.04" (1mm) of rain.

How many days does it rain in August in Guerneville?

In Guerneville, California, in August, during 0.9 rainfall days, 0.04" (1mm) of precipitation is typically accumulated.

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

The average day length in August is 13h and 37min.

When is the sunrise / sunset in August in Guerneville?

In August, on the first day of the month, sunrise is at 6:14 am and sunset at 8:21 pm. On the last day of the month, in Guerneville, sunrise is at 6:41 am and sunset at 7:42 pm PDT.

How long on average sun shines in August in Guerneville?

In Guerneville, California, the average sunshine duration in August is 11.7h.

When is the highest UV index in Guerneville?

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 Guerneville?

In Guerneville, California, the average daily maximum UV index in August is 6. A UV Index estimate of 6 to 7 represents a high hazard to health from unprotected exposure to UV radiation.
Average humidity
Average rainfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in August
Guerneville, CA

Average temperature in August - Guerneville, CA
  • Average high temperature in August: 81°F

The warmest month (with the highest average high temperature) is August (81°F).
The month with the lowest average high temperature is December (56.3°F).

  • Average low temperature in August: 53.4°F

The months with the highest average low temperature are August and September (53.4°F).
The coldest month (with the lowest average low temperature) is December (41.4°F).

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Average pressure in August
Guerneville, CA

Average pressure in August - Guerneville, CA
  • Average pressure in August: 29.92"Hg

The month with the highest atmospheric pressure is January (30.13"Hg).
The months with the lowest atmospheric pressure are June, August and September (29.92"Hg).

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Average wind speed in August
Guerneville, CA

Average wind speed in August - Guerneville, CA
  • Average wind speed in August: 5.1mph

The windiest month (with the highest average wind speed) is May (7.2mph).
The calmest month (with the lowest average wind speed) is November (5mph).

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Average humidity in August
Guerneville, CA

Average humidity in August - Guerneville, CA
  • Average humidity in August: 66%

The month with the highest relative humidity is March (77%).
The month with the lowest relative humidity is September (62%).

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Average rainfall in August
Guerneville, CA

Average rainfall in August - Guerneville, CA
  • Average rainfall in August: 0.04"

The wettest month (with the highest rainfall) is February (3.27").
The driest months (with the least rainfall) are July and August (0.04").

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Average rainfall days in August
Guerneville, CA

Average rainfall days in August - Guerneville, CA
  • Average rainfall days in August: 0.9 days

The month with the highest number of rainy days is March (10.3 days).
The month with the least rainy days is August (0.9 days).

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Average daylight in August /
Average sunshine in August
Guerneville, CA

Average daylight in August / Average sunshine in August - Guerneville, CA
  • Average daylight in August: 13h and 4min

The month with the longest days is June (Average daylight: 14h and 48min).
The month with the shortest days is December (Average daylight: 9h and 30min).

  • Average sunshine in August: 11h and 4min

The month with the most sunshine is July (Average sunshine: 11h and 48min).
The month with the least sunshine is December (Average sunshine: 5h and 24min).

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Average sunshine days in August
Guerneville, CA

Average sunshine days in August - Guerneville, CA
  • Average sunshine days in August: 28.4 days

The month with the most sunshine days is July (28.9 days).
The month with the least sunshine days is February (19.9 days).

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Average UV index in August
Guerneville, CA

Average UV index in August - Guerneville, CA
  • 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 3).

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Average cloud cover in August
Guerneville, CA

Average cloud cover in August - Guerneville, CA
  • Average cloud cover in August: 13

The month with the most cloud cover is March (Cloud cover 42).
The month with the least cloud cover is July (Cloud cover 11).

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Average visibility in August
Guerneville, CA

Average visibility in August - Guerneville, CA
  • 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).

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Guerneville, California, USA

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