Mill Valley Weather in September

Mill Valley in September sees high temperatures, with highs around 24°C (75°F) and overnight lows of 12°C (54°F). With just 5 mm (0.2 in) of rainfall on average, rain is rarely an issue.

Rainfall in Mill Valley in September

Climate statistics over the past 30 years suggest around 2 days of rain, with 5 mm (0.2 in) average for the month. The occasional light shower is possible, but rain is rarely an issue this month.

Temperature in Mill Valley in September

Mill Valley has perfect weather in September, with days reaching 24°C (75°F) and nights cooling to 12°C (54°F). The days can feel warmer than the evenings, so packing for both parts of the day is a good idea. With lows of 12°C (54°F), nights are cool. If you're out after dark, an extra layer will keep you comfortable. The cooler air at night is also great for getting a good rest. On average, it is the month with the highest temperature of the year.

Sunshine in Mill Valley in September

Expect sunny days throughout the month, with an estimated 270 hours of sunshine. This makes it a pleasant time to visit Mill Valley.

If you favor pleasant temperatures and minimal rainfall, September is one of the best months to visit Mill Valley.

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Check the conditions for any month of the year.

• January
• February
• March
• April

• May
• June
• July
• August

• September
• October
• November
• December

For a detailed overview over the year and the best time to visit the United States of America, check out our Mill Valley's climate page.

Mill Valley Temperature in September

Min Temperature 12°C (54°F)  

Max Temperature 24°C (75°F)  

Chance of Rain 7%  

Precipitation 5 mm (0.2 in)  

Rainy days 2 days  

Humidity 73% *  

Sunshine 270 hours *  

Percentage Sunshine 73% *  

* Data from: San Francisco, the United States of America (35 KM, 21 Miles).

What to Wear in Mill Valley in September

Comfortable temperatures call for an easy wardrobe in September. Pack summer basics like t-shirts and shorts, but include a light jacket for cooler moments. A pair of comfortable walking shoes is essential. Dry conditions mean you won't need to worry about rain protection. And with plenty of sunshine hours, don’t forget sunglasses, sunscreen, and maybe a sun hat.

What To Do in Mill Valley in September

We rated the following activities from 1 (least suitable) to 10 (best) to do.

Swimming

10/10

Cycling

10/10

Walking

10/10

Barbeque

9/10

Camping

10/10

Outdoor sports

10/10

Select a Month

Check the conditions for any month of the year.

• January
• February
• March
• April

• May
• June
• July
• August

• September
• October
• November
• December

For a detailed overview over the year and the best time to visit the United States of America, check out our Mill Valley's climate page.

More climate data for Mill Valley

Temperature Rainfall Sunshine Humidity

See the full Mill Valley climate overview or explore weather in the United States of America.