Costa Mesa Weather in September

Costa Mesa in September averages 27°C (81°F) during the day and 18°C (64°F) at night. Minimal rainfall is typical for this time of year.

Rainfall in Costa Mesa in September

Typically, about a single day will experience rainfall, with an average of 4.4 mm (0.2 in) for the month. If rain does fall, it tends to be a moderate shower rather than anything heavy.

Temperature in Costa Mesa in September

September is a good time to be in Costa Mesa. Days are excellent, reaching 27°C (81°F), with nights around 18°C (64°F). Overall, the month follows a fairly predictable daily temperature pattern. Nights drop to around 18°C (64°F), which is noticeably cooler than the daytime. A light jacket for the evening is a sensible addition, and the cool nights tend to make sleeping comfortable. This is typically the warmest month of the year, so light summer clothing is a good idea.

Sunshine in Costa Mesa in September

There are approximately 290 hours of sunshine this month, resulting in mostly clear days.

If you're a fan of comfortable temperatures and drier conditions, September is a great time to visit.

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• January
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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 Costa Mesa's climate page.

Costa Mesa Temperature in September

Min Temperature 18°C (64°F)  

Max Temperature 27°C (81°F)  

Chance of Rain 3%  

Precipitation 4.4 mm (0.2 in)  

Rainy days a single day  

Sunshine 290 hours *  

Percentage Sunshine *  

* Data from: Corona, the United States of America (39 KM, 24 Miles).

What to Wear in Costa Mesa in September

Warm weather calls for comfortable, breathable clothing in September. Cotton t-shirts, shorts, light dresses, and sandals are perfect. You might still want a light layer for evenings or air-conditioned places (for example buses). Almost no rain is expected, so no need to bring rain gear. You'll definitely want to pack sunglasses and sunscreen. There will be plenty of bright sunshine this month.

What To Do in Costa Mesa in September

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

Swimming

10/10

Cycling

8/10

Walking

8/10

Barbeque

10/10

Camping

10/10

Outdoor sports

8/10

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 Costa Mesa's climate page.

More climate data for Costa Mesa

Temperature Rainfall Sunshine

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