Season in Detail: May-June-July

The season of "May Gray"  and "June Gloom" for Southern California, including San Diego.  Expect lighter winds, more fog, larger crowds at the beaches.

Synoptic pressure systems have stopped moving around and are now somewhat "set" in position for the season.

One system, "The North Pacific High" (NPH), sits and spins in a clockwise fashion (with NW winds) just off the cool Central and/or Northern California coasts.  Smaller "thermal lows" sit over the inland valleys and deserts, with lots of heat from the sun.

The interaction of these two systems tends to bring solid wind to the Central and Northern California coasts as pressure tends to flow from high to low.

But this effect does not fully apply to the Southern California coast.

Due to the position of the NPH at this time of year, its solid NW wind is attenuated by the Santa Ynez mountains to Point Conception, as well as Southern California coast "sitting back" away from the flow (a geographic feature known as the Southern California Bight).  As the wind is blocked, this creates a lighter wind "void" on the waters inside the bight. With the winds attenuated, the thermal lows can build all the way to the coast as the day wears on, leaving the coast with no solid gradient for wind, and lots of heat.

However, there are times when the NPH is positioned lower or closer, which tends to send WNW winds towards the coast, keeping the thermal lows away from the coast.  If strong enough, this can generate ridable wind at all the riding sites.  These days have standard WNW winds, which usually blow 8-14MPH, with some rare plus days.  Its usually only ridable 3-7 days per month in this season.  Geographic focal points north of San Diego County (like Cabrillo, or Leo Carillo) usually boost this wind locally, making for even stronger winds, and more frequently ridable days.

Sometimes the NW flow of wind persists, and/or increases velocity on the outside waters. This begins to generate an eddy effect on the inside waters.  This creates a counter-clockwise loop inside the bight, fed on its western edge by NW winds in the outside waters.   Most of the coastal sites will show S to SE winds matching the eastern edge of the counter-clockwise flow.  In extreme cases, the flow will be strong enough for ridable winds, especially in San Diego (further south, the better), which is in the SE quadrant of the pattern.  These "eddy winds" generally blow 12-17MPH from a S to SSW direction.  Rarely is the flow strong enough to make for ridable wind any further north than San Diego.  As the winds are not directly on-shore, the thermal lows are still usually able to build to the beach as the day wears on, dropping the wind velocity, so riding these winds early is the key.