Millbrae Weather in September

Millbrae in September sees high temperatures, with highs around 23°C (73°F) and overnight lows of 13°C (55°F). With just 3.4 mm (0.1 in) of rainfall on average, rain is rarely an issue.

Rainfall in Millbrae in September

Expect around a single day of rain based on historical data, with 3.4 mm (0.1 in) average. If rain does fall, it tends to be very light and barely worth getting out an umbrella for.

Temperature in Millbrae in September

If you're visiting Millbrae in September, expect perfect temperatures with highs of 23°C (73°F) and overnight lows of 13°C (55°F). Overall, the month follows a fairly predictable daily temperature pattern. With lows of 13°C (55°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 Millbrae in September

There are approximately 270 hours of sunshine this month, resulting in mostly clear days.

Wind Speed in Millbrae in September

Wind speeds average 5 m/s (10 knots) during September. At this speed, gentle to moderate breezes make small trees sway and the wind creates whitecaps on water bodies. Daily variations range from moderate winds to stronger breezes, creating excellent conditions for sailing, kite flying and wind sports.

Average water temperature in September

The water is 14°C (57°F) this month — cool enough to feel refreshing on a warm day, but cold enough that most people won't stay in for long without a wetsuit.

Our weather planner can help you find worldwide destinations with pleasant weather during this period. May, June, July, August, September and October typically offer the best weather for Millbrae.

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• January
• February
• March
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• May
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• October
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For a detailed overview over the year and the best time to visit the United States of America, check out our Millbrae's climate page.

Millbrae Temperature in September

Min Temperature 13°C (55°F)  

Max Temperature 23°C (73°F)  

Water Temperature 14°C (57°F) *  

Chance of Rain 3%  

Precipitation 3.4 mm (0.1 in)  

Rainy days a single day  

Humidity 73% *  

Windspeed 5 m/s (10 knots) *  

Sunshine 270 hours *  

Percentage Sunshine 73% *  

* Data from: San Francisco, the United States of America (2 KM, 1 Miles).

What to Wear in Millbrae in September

For Millbrae in September, you'll want flexible clothing. It's wise to pack cotton shirts, comfortable shorts, and a pair of jeans for cooler evenings. A light sweater or jacket is useful for air-conditioned spaces (like buses) or unexpected cool moments. Almost no rain is expected, so no need to bring rain gear. With water temperatures around 14°C (57°F), the water is quite cold for swimming. You can skip the swimwear unless you're particularly tough. You'll definitely want to pack sunglasses and sunscreen. There will be plenty of bright sunshine this month.

What To Do in Millbrae 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 Millbrae's climate page.

More climate data for Millbrae

Temperature Rainfall Sunshine Humidity Wind Speed Water Temp

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