August weather forecast
Mill Valley, CA

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Weather in August

The last month of the summer, August, is also an agreeable month in Mill Valley, California, with temperature in the range of an average high of 71.2°F (21.8°C) and an average low of 55.4°F (13°C).

Temperature

As Mill Valley transitions from July to August, the average high-temperatures adjust to a still pleasant 71.2°F (21.8°C), nearly the same as the previous 70.5°F (21.4°C). Mill Valley's temperature lowers to a mean of 55.4°F (13°C) during the nights in August.

Humidity

In Mill Valley, California, the average relative humidity in August is 76%.

Rainfall

June through September are months with the least rain when the rain falls for 1.2 days and typically aggregates up to 0.04" (1mm) of rain.

Daylight

In Mill Valley, the average length of the day in August is 13h and 35min.
On the first day of August, sunrise is at 6:14 am and sunset at 8:18 pm. On the last day of the month, sunrise is at 6:40 am and sunset at 7:40 pm PDT.

Sunshine

The average sunshine in August is 10.9h.

UV index

April, June through September, with an average maximum UV index of 5, are months with the highest UV index in Mill Valley. A UV Index estimate of 3 to 5 represents a medium health hazard from exposure to the Sun's UV radiation for the average person.
Note: The maximum UV index of 5 during August translates into these guidelines:
Undertake protective steps - Preventing sun damage is advised. When the Sun's UV radiation is most intense during midday, it's best to find shade and limit exposure. For optimum UV protection, wear sun-resistant attire complemented with a hat and quality shades.
Updated: Jul 16, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What are the temperatures in August?

The high-temperature, in August, in Mill Valley, is 71.2°F (21.8°C), while the low-temperature averages to 55.4°F (13°C).

What is the average humidity in August?

In Mill Valley, the average relative humidity in August is 76%.

What is the driest month?

June through September are months with the least rain in Mill Valley when the rain falls for 1.2 days and typically aggregates up to 0.04" (1mm) of rain.

How much does it rain in August?

In Mill Valley, during August, the rain falls for 1.2 days and regularly aggregates up to 0.04" (1mm) of precipitation.

How many hours of daylight does Mill Valley have in August?

The average day length in August is 13h and 35min.

When are sunrise and sunset in August?

On the first day of August, sunrise is at 6:14 am and sunset at 8:18 pm. On the last day of the month, sunrise is at 6:40 am and sunset at 7:40 pm PDT.

How long on average sun shines in August?

The average sunshine duration in August is 10.9h.

What are the months with the highest UV index?

The months with the highest UV index in Mill Valley are April, June through September, with an average maximum UV index of 5.

How high is the UV index in August?

The average daily maximum UV index in August is 5. A UV Index value of 3 to 5 symbolizes a moderate health threat 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
Mill Valley, CA

Average temperature in August - Mill Valley, CA
  • Average high temperature in August: 71.2°F

The warmest month (with the highest average high temperature) is September (72.3°F).
The month with the lowest average high temperature is December (55.4°F).

  • Average low temperature in August: 55.4°F

The month with the highest average low temperature is September (56.1°F).
The coldest month (with the lowest average low temperature) is December (45.3°F).

Average pressure in August
Mill Valley, CA

Average pressure in August - Mill Valley, 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).

Average wind speed in August
Mill Valley, CA

Average wind speed in August - Mill Valley, CA
  • Average wind speed in August: 6.4mph

The windiest month (with the highest average wind speed) is May (7.8mph).
The calmest months (with the lowest average wind speed) are October and November (5.5mph).

Average humidity in August
Mill Valley, CA

Average humidity in August - Mill Valley, CA
  • Average humidity in August: 76%

The month with the highest relative humidity is March (77%).
The month with the lowest relative humidity is October (68%).

Average rainfall in August
Mill Valley, CA

Average rainfall in August - Mill Valley, CA
  • Average rainfall in August: 0.04"

The wettest month (with the highest rainfall) is February (0.87").
The driest months (with the least rainfall) are June, July, August and September (0.04").

Average rainfall days in August
Mill Valley, CA

Average rainfall days in August - Mill Valley, CA
  • Average rainfall days in August: 1.2 days

The month with the highest number of rainy days is March (8.8 days).
The months with the least rainy days are June and August (1.2 days).

Average daylight in August /
Average sunshine in August
Mill Valley, CA

Average daylight in August / Average sunshine in August - Mill Valley, 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 36min).

  • Average sunshine in August: 10h and 5min

The month with the most sunshine is July (Average sunshine: 11h and 12min).
The month with the least sunshine is December (Average sunshine: 5h and 30min).

Average sunshine days in August
Mill Valley, CA

Average sunshine days in August - Mill Valley, CA
  • Average sunshine days in August: 24.8 days

The month with the most sunshine days is June (26.4 days).
The month with the least sunshine days is March (20.7 days).

Average UV index in August
Mill Valley, CA

Average UV index in August - Mill Valley, CA
  • Average UV index in August: 5

The months with the highest UV index are April, June, July, August and September (UV index 5).
The months with the lowest UV index are January, February, November and December (UV index 3).

Average cloud cover in August
Mill Valley, CA

Average cloud cover in August - Mill Valley, CA
  • Average cloud cover in August: 25

The month with the most cloud cover is March (Cloud cover 39).
The month with the least cloud cover is September (Cloud cover 19).

Average visibility in August
Mill Valley, CA

Average visibility in August - Mill Valley, 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).

Mill Valley, California, USA

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