Costa Mesa

Planning a trip to Costa Mesa or just want to stay up to date with the weather? In this section, you'll find current weather information, as well as forecasts and helpful charts.

Costa Mesa in the USA features a pleasant Mediterranean climate. This means you can expect mild, occasionally damp winters and warm, very dry summers. The city boasts plenty of sunshine throughout the year, while sudden temperature fluctuations or extreme weather conditions are rare.

Costa Mesa has two distinct main seasons. Summer, especially from June to September, is characterized by warm and sunny weather with average temperatures ranging from 20°C to 24°C and almost no rainfall—an ideal time for outdoor activities. Winter, from December to March, is cooler, with average temperatures around 13-14°C. This period sees the majority, albeit small, of the annual precipitation. Spring and autumn are comfortable transitional seasons with moderate temperatures and minimal rain.

The climate in Costa Mesa is mild with pleasant temperatures throughout the year. The average annual temperature stays within a comfortable range. August is typically the hottest month, with average temperatures reaching 23.9°C and daytime highs potentially climbing to 28.5°C. January and February are considered the coolest months, with average temperatures around 13.6-13.8°C and average nightly lows dropping to 8.7-9.0°C.

The summer months in Costa Mesa, especially from June to September, are characterized by warm and mostly dry weather. Average daytime temperatures in July and August consistently stay above 23°C, with highs reaching 27-28.5°C. Nights also remain warm, with minimum temperatures around 16-19°C. Precipitation is almost non-existent in summer, making it ideal for outdoor activities. The difference between day and night temperatures in summer is about 9-10°C, providing a pleasant coolness in the evenings.

Winter in Costa Mesa, from December to March, is very mild. Average daytime temperatures during this period range from 18.5°C to 19.1°C, while nightly temperatures drop to 8.7-10.3°C. Frost is a great rarity here. While winter is a wetter season compared to summer, the amount of precipitation remains moderate, with the highest number of rainy days in March (about 9 days). Diurnal temperature fluctuations are also noticeable in winter, at around 8-11°C, so a light jacket or sweater may be useful for evening walks.

The city of Costa Mesa experiences a climate with a very clear distinction between dry and relatively wet seasons. Most of the year is characterized by minimal precipitation, which is typical for Southern California.

The period with the highest probability of precipitation occurs during the winter and early spring months, roughly from November to April. The "wettest" month in Costa Mesa is March, with an average of about 3 mm of rainfall and up to nine rainy days. January and February also see small amounts of precipitation, around 2 mm each month, with about six rainy days each. December also brings about 2 mm of precipitation over roughly five days. It's worth noting that even in these months, rainfall is usually light and brief.

From May until the end of October, Costa Mesa experiences a pronounced dry season. Precipitation is virtually non-existent during this time. July and August are particularly dry, with zero average rainfall and no recorded rainy days. June and September also have an extremely low probability of precipitation, with one or fewer rainy days and zero millimeters of rainfall. In May and October, the number of rainy days is only two, and the precipitation amounts also trend toward zero.

When planning a trip to Costa Mesa, it's worth considering its predominantly mild and sunny climate. Regardless of the time of year, you'll need comfortable walking shoes, sunscreen, sunglasses, and a hat. Layering should be your key packing principle, as temperatures can change throughout the day and depending on the season. A light jacket or cardigan, perhaps windproof, will be useful for evening strolls or visiting air-conditioned indoor spaces, especially given the occasional breeze.

During the summer months from June to September, when average temperatures hover around 20-24°C and maximums can reach 28°C, pack light and breathable clothing: shorts, t-shirts, and sundresses. Precipitation is virtually non-existent during this period. For the cooler season, especially from December to March when the average temperature is around 13-14°C, you'll need warmer items: long-sleeved shirts, sweaters, and a medium-weight jacket. Although rainfall in Costa Mesa is rare (only about 0-3 mm in most months), these winter months (especially January, February, and March) see a few rainy days (up to 6-9 days with 2-3 mm of precipitation), so a compact umbrella or a light waterproof jacket might come in handy.