Climate and monthly weather forecast
Mill Valley, CA

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Weather in January

January, like December, is another mild winter month in Mill Valley, California, with temperature in the range of an average low of 45.5°F (7.5°C) and an average high of 56.1°F (13.4°C). Transitioning from December to January, Mill Valley observes an average high-temperature of a still refreshing 56.1°F (13.4°C), differing subtly from the previous month. Weather in January »

Weather in February

February, the last month of the winter in Mill Valley, is also a moderate month, with an average temperature varying between 57.9°F (14.4°C) and 45.9°F (7.7°C). The onset of February manifests an average high-temperature of a still moderate 57.9°F (14.4°C), demonstrating a minor variation from the preceding month. Weather in February »

Weather in March

The first month of the spring, March, is also a moderate month in Mill Valley, California, with an average temperature varying between 59.4°F (15.2°C) and 46.9°F (8.3°C). March denotes a minimal variation in the average high-temperature to a still moderate 59.4°F (15.2°C) from February's 57.9°F (14.4°C). Weather in March »

Weather in April

April is a refreshing spring month in Mill Valley, California, with an average temperature ranging between max 62.8°F (17.1°C) and min 48.6°F (9.2°C). Mill Valley registers an average high-temperature of a comfortable 62.8°F (17.1°C) with the arrival of April, showing minor deviation from the preceding month. Weather in April »

Weather in May

May, the last month of the spring in Mill Valley, is also an enjoyable month, with an average temperature ranging between max 64.9°F (18.3°C) and min 50.4°F (10.2°C). Mill Valley's May reports an average high-temperature of a still enjoyable 64.9°F (18.3°C), exhibiting a minor difference from April. Weather in May »

Weather in June

June, the first month of the summer in Mill Valley, is an agreeable month, with an average temperature ranging between max 69.1°F (20.6°C) and min 53.2°F (11.8°C). June's onset records an average high-temperature of an agreeable 69.1°F (20.6°C), a near match to May's 64.9°F (18.3°C). Weather in June »

Weather in July

July, the same as June, in Mill Valley, California, is an agreeable summer month, with an average temperature varying between 70.5°F (21.4°C) and 54.3°F (12.4°C). Transitioning from June to July, Mill Valley observes an average high-temperature of a still agreeable 70.5°F (21.4°C), differing subtly from the previous month. Weather in July »

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). 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). Weather in August »

Weather in September

The first month of the autumn, September, is still a pleasant month in Mill Valley, California, with an average temperature varying between 56.1°F (13.4°C) and 72.3°F (22.4°C). Temperature readings reach their annual highs in September, averaging 72.3°F (22.4°C) and a minimum average of 56.1°F (13.4°C). Weather in September »

Weather in October

October, like September, is an agreeable autumn month in Mill Valley, California, with an average temperature ranging between min 54.3°F (12.4°C) and max 68.9°F (20.5°C). Mill Valley commences October with an average high-temperature of a still pleasant 68.9°F (20.5°C), maintaining a close resemblance to the previous month. Weather in October »

Weather in November

The last month of the autumn, November, is another comfortable month in Mill Valley, California, with temperature in the range of an average high of 61.5°F (16.4°C) and an average low of 49.6°F (9.8°C). The arrival of November corresponds with a light shift in temperature, down from an agreeable 68.9°F (20.5°C) in October to a comfortable 61.5°F (16.4°C). Weather in November »

Weather in December

The first month of the winter, December, is still a refreshing month in Mill Valley, California, with an average temperature ranging between max 55.4°F (13°C) and min 45.3°F (7.4°C). The coldest period tends to be December, when average temperatures fluctuate between a high of 55.4°F (13°C) and a low of 45.3°F (7.4°C). Weather in December »
Updated: Jul 16, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

How many days does it rain?

Throughout the year, there are 48 rainfall days, and 3.94" (100mm) of precipitation is accumulated.

What are the months with the lowest UV index?

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

What is the wettest month?

February is the month with the most rainfall. Rain falls for 5.3 days and accumulates 0.87" (22mm) of precipitation.

What is the most humid month?

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

When is Daylight Saving Time (DST)?

On Sunday, March 10. 2024, at 2:00 am, Daylight Saving Time starts, and the time zone changes from PST to PDT. Daylight Saving Time ends Sunday, November 3. 2024, at 2:00 am, and the time zone reverts from PDT to PST.

When is the highest UV index?

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

What is the driest month?

The months with the least rainfall are June through September Rain falls for 1.2 days and accumulates 0.04" (1mm) of rain.

When are the longest days?

June has the longest days of the year, with an average of 14h and 48min of daylight.

What month has the most sunshine?

With an average of 11.2h of sunshine, July has the most sunshine of the year.

What time of the year is the hottest?

Mill Valley's warmest month, September, generally records average temperatures ranging from a high of 72.3°F (22.4°C) to a low of 56.1°F (13.4°C).

What is the least humid month in Mill Valley?

With an average relative humidity of 68%, October is the least humid month.

What month is the coldest?

Mill Valley experiences its lowest temperatures in December, with an average peak of 55.4°F (13°C) and a low of 45.3°F (7.4°C).

What is the month with the shortest days?

December has the shortest days of the year, with an average of 9h and 36min of daylight.

What is the month with the least sunshine?

With an average of 5.5h of sunshine, December has the least sunshine of the year.

Average temperature
Mill Valley, CA

Average temperature - Mill Valley, CA

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).

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
Mill Valley, CA

Average pressure - Mill Valley, CA

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
Mill Valley, CA

Average wind speed - Mill Valley, CA

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
Mill Valley, CA

Average humidity - Mill Valley, CA

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

Average rainfall
Mill Valley, CA

Average rainfall - Mill Valley, CA

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
Mill Valley, CA

Average rainfall days - Mill Valley, CA

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 / Average sunshine
Mill Valley, CA

Average daylight / Average sunshine - Mill Valley, CA

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).

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
Mill Valley, CA

Average sunshine days - Mill Valley, CA

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
Mill Valley, CA

Average UV index - Mill Valley, CA

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 visibility
Mill Valley, CA

Average visibility - Mill Valley, CA

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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