The opening to the sea is, of course, the Golden Gate. When the temp's in the central valley of Sacramento rise, they create huge up drafts. The displaced air is replaced by wind
currents that sweep in from the sea draging the marine
layer of clouds thru what local sailors call the "slot". This is what causes fog
in SF, and generates the 25 knot
winds most afternoons. Cold clammy conditions are the norm for the Bay north of the Bay Bridge while the sunshines to the south of the bridge.
and South San Francisco
are influnced by winds that sweep around the south side of San Bruno. Jets takeoff from SFO at a rate of one a minute and at these marinas
in this local, conversations must be suspended while tha jets pass over head
. When I lived at one of these marinas, I'd wait until after dark to return to my slip so I wouldn't be required to make a 90* turn from the fairway to my slip in the 25 to 30 knot
afternoon breeze. Nightfall brought calm condidtions.
Pier 39 is on pilings close to the tideal race
known as the entrance to the Bay. At the Gate the yearly tidal range is eight feet, the max current
is a bit over 4 knots for either the two flood cycles or the two ebb cycles each day. Conditions have not improved in the short distance to Pier 39. That's quite a bit of water
sluicing back and forth.
Consider the marinas in Alamada. Great weather
, a delightful island and a short ferryboat ride to downtown San Francisco