Catalina Eddy and June Gloom: They sound like a pair of grifters straight out of Raymond Chandler. To many people, these climatic features are indeed villains, cheating Southern Californians of their inalienable right to summer sunshine.
I happen to love this respite of gray before summer's blue-skied perfection settles in. The June Gloom keeps the coastal sage scrub in bloom a little longer and extends the prime hiking season at lower elevations for a few more weeks.
The phenomenon is caused as northwest winds move down the Southern California coast. South of Point Conception, the winds begin to turn counterclockwise when they bump up against land, creating a low-pressure swirl called the Catalina Eddy. The ensuing southerly wind shift increases existing fog and promotes new fog formation. The result is a deepening marine layer, aka June Gloom.
June Gloom can make a good hike even more memorable. Hiking beneath the veil, the temperature is a good 20° cooler than in the sun. If the fog does retreat, you'll get spectacular views of ridges emerging from the mist into the bright, inevitable summer sun.
With easy canyon-floor trails and more challenging ridge routes, Zuma Canyon (free; www.nps.gov/samo or 805/370-2301), inland from Zuma Beach off Pacific Coast Hwy. in Malibu, is great for June Gloom hiking.