Weather Averages in Orange County
The Climate of Orange County is an annual mild to hot and mostly dry climate. The climate is classified as a Mediterranean climate, which is a type of dry subtropical climate. It is characterized by seasonal changes in rainfall—with a dry summer and a winter rainy season. Under the modified Köppen climate classification, the coastal areas are classified as Csb, and the inland areas as Csa.
The Los Angeles metropolitan area (includes Orange County) as a whole contains microclimates, where daytime temperatures can vary as much as 36 °F (20 °C) between inland areas such as the San Fernando Valley or San Gabriel Valley, and the coastal Los Angeles Basin.
Orange County is a hot-summer mediterranean climate (Köppen Csa), with hot, dry summers, and cooler wetter winters. While the typical dry-summer and wet-winter pattern typical of most Mediterranean climates is part of the climate of Los Angeles, precipitation annually is lower than in many typical Mediterranean climates.
The summer dry season normally runs from June through October, when clear skies, hot temperatures, and very little change in sensible weather occur from day to day. Average high temperatures are in the lower 80’s F (26-28 C) with overnight lows in the lower 60’s F (15-17 C). During this season, there is essentially no rainfall, and both July and August average less than 0.05 of an inch (1.27 mm) of monthly precipitation.
The winter wet season normally runs from November through early May. Precipitation episodes in Orange County, with a few notable exceptions, are largely caused by extratropical disturbances approaching California from the west or northwest during the winter season. The normal seasonal rainfall measured in the metropolitan area is 14.77 inches, of which 92% falls between November 1st and April 30th.  While there is a great increase in rainfall in the winter months, the winter months in Orange County are still frequently sunny and pleasant with mild temperatures. The average highs range from the upper 60’s F to 70 F (17-21 C) with cooler overnight lows in the upper 40’s and lower 50’s F (8-12 C).
Rainfall, on average, is frequently below average. Most rain occurs during the winter and early to mid-spring, typical of a Mediterranean climate. However, the amount received is usually lower than in other Mediterranean climates. The first sporadic rainfall of the rainy season usually occurs in October or November, with heavy rain becoming more common December through early April. Usually the Pineapple Express storms from November to January. February, on average, is the wettest month. The rains then taper off in April or by May, usually see only two to three light rain showers. However, the timing and volume of rains in the winter is far from predictable. After a significant rain, the region’s air is cleared of the usual atmospheric haze as well as man-made smog, giving exceptionally clear views across the giant metropolis.