Costa Mesa, California —features weather that enjoys ocean breezes and cooling influences that make for pleasant temperatures year round. One of the biggest events, the Orange Country Fair, in Costa Mesa is held in the months of July and August, and usually features warm weather with occasional heating trends. With highs that have peaked at 107 degrees in July, heat spells are not rare and you may encounter temperatures in the 90s during the fair event. You'll seldom experience rain during the summer, however.
The average rainfall each year is low, with no more than 15 inches on an average year and usually less.
When you visit Costa Mesa, you can expect temperatures just slightly higher than nearby beach weather in Newport Beach. 2 to 5 degrees warmer temps would normally be the range of weather you can expect.
The highest recorded temperature was 107°F in 1963 and the lowest recorded temperature was 28°F in 1966.