Elevation
2 to 3 m (7 to 10 ft.)

Precipitation

Average precipitation: 30 cm (12 in.) per year.

Download seasonal and monthly total precipitation since 1961 (pdf file as recorded by the Costa Mesa station see map below)

Orange County Historic Data web site   

Average Temperatures

September maximum: 29 ºC (86 ºF)
January minimum: 4 ºC (40 ºF)
Annual mean: 17 ºC (62 ºF)

Wunderground San Joaquin Marsh weather station