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Hourly Forecast
Daylight Hours
06:40
Sunrise
18:52
Sunset
Moon
Waxing Crescent
11:15
Moonrise
20:46
Moonset
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Weather in Costa Mesa today, September 15, 2026
Expect a muted, overcast feel in Costa Mesa on September 15, 2026 as cloud persists. Brighter breaks, if they arrive, should stay brief.
Expect highs of 24°C and cooler readings close to 20°C. The air stays humid, with relative humidity between 64% and 82% and the peak around 21:00. Winds stay light, near 4.5 km/h by 15:00, so the day feels still more than breezy.
Afternoon skies stay clogged, peaking close to 100% near 16:00. The grey theme continues rather than clearing out. Visibility stays near 16.1 km. Sunrise is at 06:40 and sunset at 18:52, giving 12 hours 11 minutes of sunlight today.
Taken together, overcast skies in Costa Mesa on September 15, 2026 favour indoor or covered options, with temperatures near 24°C.
Frequently asked questions about weather in Costa Mesa
How warm does it get in Costa Mesa?
The warmest month in Costa Mesa is August, with average high temperatures of 27°C. The average temperature during this period is around 23°C.
How cold does it get in Costa Mesa?
The coldest month in Costa Mesa is January, with average low temperatures of 10°C. The average temperature during this period is around 14°C.
What is the wettest time of year in Costa Mesa?
The wettest month in Costa Mesa is January, with an average of 74mm of precipitation.
What is the driest time of year in Costa Mesa?
The driest month in Costa Mesa is July, with an average of 1mm of precipitation.
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