Castro Valley Weather in September

Thinking of visiting Castro Valley in September? Expect high temperatures reaching 25°C (77°F) during the day, dropping to 13°C (55°F) at night, with minimal rainfall.

Rainfall in Castro Valley in September

Climate statistics over the past 30 years suggest around a single day of rain, with 4.2 mm (0.2 in) average for the month. On the rare occasion it rains, expect a brief, moderate shower rather than a heavy downpour.

Temperature in Castro Valley in September

September is one of the better months to visit Castro Valley. Expect 25°C (77°F) during the day and 13°C (55°F) at night. Summer occurs in September. 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 sees the highest temps of the year.

Sunshine in Castro Valley in September

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

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

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Check the conditions for any month of the year.

• January
• February
• March
• April

• May
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• 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 Castro Valley's climate page.

Castro Valley Temperature in September

Min Temperature 13°C (55°F)  

Max Temperature 25°C (77°F)  

Chance of Rain 3%  

Precipitation 4.2 mm (0.2 in)  

Rainy days a single day  

Humidity 73% *  

Sunshine 270 hours *  

Percentage Sunshine 73% *  

* Data from: San Francisco, the United States of America (27 KM, 17 Miles).

What to Wear in Castro Valley in September

For Castro Valley 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. And with plenty of sunshine hours, don’t forget sunglasses, sunscreen, and maybe a sun hat.

What To Do in Castro 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 Castro Valley's climate page.

More climate data for Castro Valley

Temperature Rainfall Sunshine Humidity

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