Monthly weather forecast and climate
Guerneville, CA

Weather in January

January, the same as December, in Guerneville, California, is a moderate winter month, with average temperature varying between 42.3°F (5.7°C) and 57.7°F (14.3°C). In January, the average high-temperature is relatively the same as in December - a still moderate 57.7°F (14.3°C). Weather in January »

Weather in February

The last month of the winter, February, is another mild month in Guerneville, California, with average temperature ranging between max 59.2°F (15.1°C) and min 41.9°F (5.5°C). In February, the average high-temperature is essentially the same as in January - a still moderate 59.2°F (15.1°C). Weather in February »

Weather in March

The first month of the spring, March, is also a moderate month in Guerneville, California, with temperature in the range of an average low of 43°F (6.1°C) and an average high of 60.6°F (15.9°C). In March, the average high-temperature is almost the same as in February - a still mild 60.6°F (15.9°C). Weather in March »

Weather in April

April in Guerneville, California, is an enjoyable spring month, with average temperature varying between 44.8°F (7.1°C) and 65.7°F (18.7°C). In April, the average high-temperature is relatively the same as in March - an enjoyable 65.7°F (18.7°C). Weather in April »

Weather in May

May, the last month of the spring, in Guerneville, is an agreeable month, with average temperature fluctuating between 47.5°F (8.6°C) and 69.6°F (20.9°C). In Guerneville, the average high-temperature is almost the same as in April - an agreeable 69.6°F (20.9°C). Weather in May »

Weather in June

The first month of the summer, June, is a moderately hot month in Guerneville, California, with average temperature fluctuating between 77.2°F (25.1°C) and 51.8°F (11°C). In Guerneville, the average high-temperature in June slightly increases, from an agreeable 69.6°F (20.9°C) in May, to a warm 77.2°F (25.1°C). Weather in June »

Weather in July

July, like June, in Guerneville, California, is another warm summer month, with average temperature ranging between min 53.1°F (11.7°C) and max 80.2°F (26.8°C). In Guerneville, the average high-temperature is essentially the same as in June - a still warm 80.2°F (26.8°C). Weather in July »

Weather in August

August, the last month of the summer, in Guerneville, is another warm month, with average temperature varying between 81°F (27.2°C) and 53.4°F (11.9°C). August is the warmest month, with an average high-temperature of 81°F (27.2°C) and an average low-temperature of 53.4°F (11.9°C). The average heat index is evaluated at 83.8°F (28.8°C). Weather in August »

Weather in September

The first month of the autumn, September, is also a moderately hot month in Guerneville, California, with temperature in the range of an average high of 79.9°F (26.6°C) and an average low of 53.4°F (11.9°C). In Guerneville, the average high-temperature is almost the same as in August - a still warm 79.9°F (26.6°C). Weather in September »

Weather in October

October, the same as September, in Guerneville, California, is an agreeable autumn month, with average temperature fluctuating between 50.5°F (10.3°C) and 72.5°F (22.5°C). In Guerneville, California, the average high-temperature slightly decreases, from a warm 79.9°F (26.6°C) in September, to a pleasant 72.5°F (22.5°C). Weather in October »

Weather in November

The last month of the autumn, November, is also an enjoyable month in Guerneville, California, with temperature in the range of an average high of 63.5°F (17.5°C) and an average low of 45.3°F (7.4°C). In Guerneville, the average high-temperature in November decreases, from a pleasant 72.5°F (22.5°C) in October, to an enjoyable 63.5°F (17.5°C). Weather in November »

Weather in December

The first month of the winter, December, is also a moderate month in Guerneville, California, with average temperature fluctuating between 56.3°F (13.5°C) and 41.4°F (5.2°C). With an average high-temperature of 56.3°F (13.5°C) and an average low-temperature of 41.4°F (5.2°C), December is the coldest month. Weather in December »
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FAQ

How many days does it rain in Guerneville?

In Guerneville, during the entire year, the rain falls for 60.1 days and collects up to 12.87" (327mm) of precipitation.

What is the month with the lowest UV index in Guerneville?

Months with the lowest UV index in Guerneville are January, February, November and December, with an average maximum UV index of 3.

What is the rainiest month in Guerneville?

February is the month with the most rainfall in Guerneville, California. Rain falls for 7.3 days and accumulates 3.27" (83mm) of precipitation.

What is the most humid month in Guerneville?

The most humid month is March, with an average relative humidity of 77%.

When are the longest days in Guerneville?

With an average of 14.8h of daylight, June has the longest days of the year.

What is the month with the highest UV index in Guerneville?

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

What is the driest month in Guerneville?

July and August are months with the least rain in Guerneville, California, when the rain falls for 1.3 days and typically aggregates up to 0.04" (1mm) of rain.

What month has the most sunshine in Guerneville?

July has the most sunshine of the year, with an average of 11.8h of sunshine.

What is the warmest month in Guerneville?

The warmest month in Guerneville is August, with an average high-temperature of 81°F (27.2°C) and an average low-temperature of 53.4°F (11.9°C).

What is the least humid month in Guerneville?

September is the least humid month, with an average relative humidity of 62%.

What is the coldest month in Guerneville?

With an average high-temperature of 56.3°F (13.5°C) and an average low-temperature of 41.4°F (5.2°C), December is the coldest month.

What is the month with the shortest days in Guerneville?

The month with the shortest days in Guerneville is December, with an average of 9.5h of daylight.

What is the month with the least sunshine in Guerneville?

With an average of 5.4h of sunshine, December has the least sunshine of the year.

Average temperature
Guerneville, CA

Average temperature - Guerneville, CA

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).

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
Guerneville, CA

Average pressure - Guerneville, CA

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

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Average wind speed
Guerneville, CA

Average wind speed - Guerneville, CA

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
Guerneville, CA

Average humidity - Guerneville, CA

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
Guerneville, CA

Average rainfall - Guerneville, CA

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
Guerneville, CA

Average rainfall days - Guerneville, CA

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 / Average sunshine
Guerneville, CA

Average daylight / Average sunshine - Guerneville, CA

The month with the longest days is June (Average daylight: 14.8h).
The month with the shortest days is December (Average daylight: 9.5h).

The month with the most sunshine is July (Average sunshine: 11.8h).
The month with the least sunshine is December (Average sunshine: 5.4h).

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Average sunshine days
Guerneville, CA

Average sunshine days - Guerneville, CA

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
Guerneville, CA

Average UV index - Guerneville, CA

Months with the highest UV index are June, July and August (UV index 6).
Months with the lowest UV index are January, February, November and December (UV index 3).

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Average visibility
Guerneville, CA

Average visibility - Guerneville, CA

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

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