Traditional American holidays such as Thanksgiving and Christmas, as well as the summer months between June and August, make up the high season in Orange County. Around these times, you can expect beaches, malls, and movie theaters to get very crowded and parking to get much harder to find.
Low travel season is between January and April. It is during these months that you have the best chance of finding cheap flights in and out of John Wayne Airport. Shoulder season falls on May and September into October.
Because the climate in Orange County is pretty comfortable year-round, there are few bad times to visit. Summers are hot, with highs in the 80s. Winters are cooler and sometimes rainy, with average temperatures in the mid to high 60s.
There are, however, two weather phenomena in Orange County to be mindful of: the Santa Ana winds and June gloom. Hot and very dry, the Santa Ana winds blow through Southern California from October to November and are typically responsible for the brush fires that occur around this time. They are also responsible for spreading dust, pollens, and other irritants in the air. Also, June can be considered a bad month for visitors since the overcast skies that characterize June gloom dominate. Other than that, Southern California has beautiful West Coast weather most days of the year.