You won’t see this snow scene anywhere near the coast in San Diego County!
It just really does not get that cold.
San Diego enjoys a semi-arid climate, often referred to as “Mediterranean” – generally sunny weather throughout the year.
If you have visited Southern France, on the Mediterranean Sea, our climate in San Diego is pretty similar.
The climate in San Diego often varies dramatically over short geographical distances, due to the topography, the numerous hills, mountains, and canyons and of course the ocean.
La Jolla and Del Mar’s climate.
The two towns are pretty close to each other, right on the ocean, sharing the same coastal climate (see below). However, there are some micro climates, even within these towns. The southern slopes of the hills, for instance are warmer that those that face west, especially those that face north.
May Grey and June Gloom – the “Marine Layer” is a factor for both of these communities.
Rancho Santa Fe’s climate.
Rancho Santa Fe is about 4 miles from the coast and about 4 miles wide. The western edges are slightly warmer than La Jolla or Del Mar, but on the eastern extremities temperatures can be as much as 10 degrees higher.
Being far enough inland, Rancho Santa Fe very rarely suffers from May Grey and June Gloom, which is a plus for some.
Santa Anna Winds
September and October often bring hot eastern winds bring hot, dry air from the inland deserts, producing what are usually the hottest days of the year. Temperatures soar to very high readings only on rare occasions. The wind’s power and dryness usually causes more problems than the heat itself. This period is also when the fire risk is at it’s highest.
No hurricanes in San Diego.
The cold California Current off the coast of California keeps ocean water cold enough, that virtually all northbound hurricanes dissipate over Baja California (Mexico) and fails to bring any precipitation to San Diego.
Breakdown of San Diego County Climate Zones
San Diego’s coastal area enjoys a mild marine climate because the Pacific Ocean is comparatively warm. The winters are mild, the summers are cool, and the air seldom really dry, unless there is a Santa Anna wind from the east.
The average high temperature range: From 65 degrees during the winter to 77 degrees in the summer. It is rare to see temperatures in the 90. The lows range from 48 degrees in the winter to 66 degrees in the summer. There are a few days during the winter when highs only reach the upper 50s.
During May and June, a thick “marine layer” cloud cover keeps the air cool and damp within a few miles of the coast, but yields to bright cloudless sunshine about 5 and 15 miles inland. This fog layer quite often burns off by midday, bathing the coastal areas with warm Southern California sunshine. This fog layer is referred to locally as May Grey and June Gloom.
The coast averages about 10 inches (250 mm) of precipitation annually, with only an average of three thunderstorms a year. From November to March, Coastal San Diego averages from 1 – 2 inches of rain per month, but it is rare to see rain between May and September.
The average high temps range from 69 degrees during the winter to 88 degrees in the summer, with temperatures occasionally reaching 90 °F (32 °C) or higher. Low temperatures average from 41 degrees in the winter to 64 degrees in the summer. Because temperatures rarely drop very far below 30°F (–1°C), this is fine citrus growing country.
In the mountains high average temps ranges from 55 degrees in the winter to 91 degrees in the summer with the lows ranging from 35 degrees in the winter to 54 degrees in the summer. Snow and ice typically occurring at higher elevations in the mountains 20 to 30 miles inland, such as Alpine, Palomar or Julian. Tire chains are usually required if you want to go sledding.
In the inland desert areas, the temperature can fluctuate as much as 30 degrees in one day, with temperatures in the summer over 100 degrees, occasionally during the spring and fall too. High average temps from 69 degrees in the winter to 107 degrees in the summer. Lows from 43 degrees in the winter to 75 degrees in the summer.