Costa Mesa (CA) Weather & Climate: Best Time to Visit
Average temperatures, rainfall, sunshine and the best time to visit Costa Mesa.
Climate overview of Costa Mesa
The climate in Costa Mesa, California, United States of America, sees a moderate range of temperatures across the year, from 27°C (81°F) in September down to 19°C (66°F) in December.
The city has an arid climate, receiving only 202 mm (8 in) of rainfall per year. Sunshine peaks in July, when the city sees around 12.3 hours of sunshine per day.
Costa Mesa Weather by Month
Pick a month to see the average temperature, rainfall and sunshine in Costa Mesa - and find the best time to visit.
Monthly Temperature in Costa Mesa
The weather in Costa Mesa changes moderately throughout the year, offering enough variation to appreciate each season. On average, daytime temperatures range from a comfortable 27°C (81°F) in September to a pleasant 19°C (66°F) in December.
Nighttime temperatures range from 19°C (66°F) in September to 9°C (48°F) in December.
Check out our detailed temperature page for more information.
Temperature ranges by month
Rainfall in Costa Mesa
Costa Mesa sits in an arid zone with minimal moisture, averaging 202 mm (8 in) of rainfall per year. The seasons in Costa Mesa bring significant changes in precipitation. The wettest month, December, receives moderate rainfall, with an average of 55 mm (2.2 in) of precipitation. This rainfall is distributed across 7 rainy days.
In contrast, the driest month, August, experiences much less rainfall, totaling 0.1 mm (0 in) over 0 rainy days. These distinct seasonal differences provide diverse experiences throughout the year. For more details, please visit our Costa Mesa Precipitation page.
The mean monthly precipitation over the year, including rain, hail, and snow
The average number of days each month with precipitation
Sunshine Hours in Costa Mesa
In Costa Mesa, summer days are longer and more sunny, with daily sunshine hours peaking at 12.3 hours in July. As the darker season arrives, the brightness of the sun becomes less. January sees a soft sun for only 6.6 hours per average day.
Visit our detailed sunshine hours page for more information.
Monthly hours of sunshine
Daily hours of sunshine
Best Time to Visit Costa Mesa
Monthly ratings reflect general weather comfort, based on daytime temperature and rainfall. Swimming and winter conditions are highlighted separately where relevant.
- Best overall: January, February, March, April, May, June, July, August, September, October and November
- Warmest weather: July, August and September
- Most sunshine: July and August
- Fewer rainy days: May, June, July, August and September
- Seasonal pattern: very little rainfall for most of the year
Frequently asked questions about the climate in Costa Mesa
What is the best time to visit Costa Mesa?
January, February, March, April, May, June, July, August, September, October and November typically offer the most optimal weather in Costa Mesa. In contrast, December tends to have less optimal conditions. Costa Mesa has very little rainfall for most of the year.
What temperatures can I expect in Costa Mesa?
Daytime highs range from 19°C (66°F) in December to 27°C (81°F) in September. Nighttime lows range from 9°C (48°F) to 19°C (66°F).
How much rain does Costa Mesa get?
Annual rainfall is around 202 mm (8 in). December is the wettest month with 55 mm (2.2 in), while August is the driest with 0.1 mm (0 in).
How sunny is Costa Mesa?
Costa Mesa receives around 3,279 hours of sunshine per year. July is the sunniest month with 369 hours, while January is the cloudiest with just 198 hours. Overall, Costa Mesa enjoys abundant sunshine.
Costa Mesa 3-Day Forecast
Costa Mesa (CA) 3-Day Forecast
Costa Mesa on the map
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