Costa Mesa, CA Weather by Month and Climate Averages

How much rain does Costa Mesa get?

Costa Mesa gets 9.4 in of precipitation in an average year, spread over about 35 days with measurable rain. That is fewer rainy days than 90% of the US.

February is the wettest month, with 2.4 in. August is the driest, with 0.0 in. January has the most rainy days, about 6.

The longest dry spell in the last five years lasted 139 days, to September 8, 2022.

See where Costa Mesa ranks: rainiest cities in the US, US cities with the most rainy days, rainiest cities in California.

Costa Mesa weather by month

Costa Mesa weather in January

In January, Costa Mesa averages a high of 64°F and a low of 50°F. It gets 2.2 in of precipitation over about 6 rainy days. The sun is out about 53% of daylight hours. The January record high is 87°F (1983) and the record low is 30°F (1971). January is one of the most comfortable months to visit.

Costa Mesa weather in February

In February, Costa Mesa averages a high of 63°F and a low of 51°F. It gets 2.4 in of precipitation over about 6 rainy days. The sun is out about 60% of daylight hours. The February record high is 91°F (2022) and the record low is 31°F (1971).

Costa Mesa weather in March

In March, Costa Mesa averages a high of 64°F and a low of 53°F. It gets 1.3 in of precipitation over about 5 rainy days. The sun is out about 52% of daylight hours. The March record high is 86°F (1978) and the record low is 37°F (1977). March is one of the most comfortable months to visit.

Costa Mesa weather in April

In April, Costa Mesa averages a high of 65°F and a low of 55°F. It gets 0.6 in of precipitation over about 3 rainy days. The sun is out about 55% of daylight hours. The April record high is 101°F (2022) and the record low is 38°F (1970). April is one of the most comfortable months to visit.

Costa Mesa weather in May

In May, Costa Mesa averages a high of 66°F and a low of 59°F. It gets 0.2 in of precipitation over about 1 rainy days. The sun is out about 48% of daylight hours. The May record high is 95°F (2014) and the record low is 39°F (2000). May is one of the most comfortable months to visit.

Costa Mesa weather in June

In June, Costa Mesa averages a high of 68°F and a low of 61°F. It gets 0.1 in of precipitation over about 1 rainy days. The sun is out about 56% of daylight hours. The June record high is 102°F (1981) and the record low is 51°F (1980). June is one of the most comfortable months to visit.

Costa Mesa weather in July

In July, Costa Mesa averages a high of 71°F and a low of 65°F. It gets 0.0 in of precipitation over about 1 rainy days. The sun is out about 71% of daylight hours. The July record high is 88°F (1985) and the record low is 56°F (1975). July is one of the most comfortable months to visit.

Costa Mesa weather in August

In August, Costa Mesa averages a high of 73°F and a low of 65°F. It gets 0.0 in of precipitation over about 0 rainy days. The sun is out about 71% of daylight hours. The August record high is 94°F (1991) and the record low is 55°F (1981). August is one of the most comfortable months to visit.

Costa Mesa weather in September

In September, Costa Mesa averages a high of 73°F and a low of 64°F. It gets 0.1 in of precipitation over about 1 rainy days. The sun is out about 68% of daylight hours. The September record high is 98°F (1970) and the record low is 52°F (1971). September is one of the most comfortable months to visit.

Costa Mesa weather in October

In October, Costa Mesa averages a high of 71°F and a low of 60°F. It gets 0.3 in of precipitation over about 2 rainy days. The sun is out about 66% of daylight hours. The October record high is 95°F (1983) and the record low is 32°F (1971). October is one of the most comfortable months to visit.

Costa Mesa weather in November

In November, Costa Mesa averages a high of 68°F and a low of 55°F. It gets 0.6 in of precipitation over about 3 rainy days. The sun is out about 66% of daylight hours. The November record high is 92°F (2010) and the record low is 38°F (1994). November is one of the most comfortable months to visit.

Costa Mesa weather in December

In December, Costa Mesa averages a high of 64°F and a low of 50°F. It gets 1.6 in of precipitation over about 6 rainy days. The sun is out about 48% of daylight hours. The December record high is 86°F (1998) and the record low is 32°F (1971). December is one of the most comfortable months to visit.

Sunshine, humidity and wind in Costa Mesa

July is the sunniest month in Costa Mesa, with sunshine about 71% of daylight hours. May is the cloudiest, at 48%. Over the year the sun shines about 60% of daylight hours. Costa Mesa is sunnier than 85% of the US.

Humidity peaks in May at 72% and is lowest in November at 59%.

Costa Mesa has about 2 days a year above 90°F. Costa Mesa is cooler than 99% of the US.

See where Costa Mesa ranks: sunniest cities in the US, cloudiest cities in the US, hottest cities in the US.

Costa Mesa weather records

The hottest temperature on record at the Costa Mesa station is 102°F, on June 15, 1981. The coldest is 30°F, on January 5, 1971.

The wettest day on record brought 6.0 in of rain, on December 6, 1997.

21 all-time records have been set at the station since 1970.

The annual mean temperature has changed by +0.4°F per decade since 1970.

The best time to visit Costa Mesa

The most comfortable time to visit is typically January and March to December, when daytime highs sit near 68°F.

Winter (December–February) is mild, with average highs around 64°F and lows near 51°F.

Spring (March–May) is mild, with average highs around 65°F and lows near 56°F.

Summer (June–August) is warm, with average highs around 71°F and lows near 64°F. It can feel humid.

Autumn (September–November) is warm, with average highs around 71°F and lows near 60°F.

Costa Mesa climate questions

How much rain does Costa Mesa get?

Costa Mesa gets 9.4 in of precipitation in an average year, over about 35 rainy days.

What is the wettest month in Costa Mesa?

February is the wettest month in Costa Mesa, with 2.4 in. August is the driest, with 0.0 in.

How many rainy days does Costa Mesa have a year?

Costa Mesa has about 35 days with measurable rain in an average year. January has the most, about 6.

What is the hottest month in Costa Mesa?

August is the warmest month in Costa Mesa, with an average high of 73°F.

What is the coldest month in Costa Mesa?

January is the coldest month in Costa Mesa, with an average low of 50°F.

What is the record high temperature in Costa Mesa?

The record high at the Costa Mesa station is 102°F, set on June 15, 1981. The record low is 30°F, on January 5, 1971.

What is the sunniest month in Costa Mesa?

July is the sunniest month in Costa Mesa, with sunshine about 71% of daylight hours. May is the cloudiest.

What is the best time to visit Costa Mesa?

The most comfortable time to visit is typically January and March to December, when daytime highs sit near 68°F.