I kiteboard in San Diego and we're constantly frustrated by our
consistent low thermal winds.  Other than occaisional Santa Anas and
storm winds, we get averages of around 10 kts a day, while it howls
every summer just north in LA county or South in, say, San Quintin. 
However, old windsurfers from the area claim that it used to blow much
better say 10 or 20 years ago.  I think this is the old "the older I
get, the better it was" going on, but my brother believes them.  Can
you, for 100 points, tell me if the wind actually was better years
ago, and if so, what happened, and what can I do to change it back?
(Will, say, covering a mountain range in blacktop help?)

If the predominate wind is an offshore one, coming from inland, the
stories about the wind being better back in the good old days may be
true.  Years ago  - decades -  I read that sailors on Long Islaand
Sound had the same complaint.  One explaination was that the the
increase in roads and other paved areas created thermal updrafts that
blocked the wind from the south at water level.

For offshore winds in San Diego, certainly a similar cause could be in effect.

From this site, however, the prevailing when seems to be WNW.  I can
only wonder if the same effect  - if it is one -  could effect the
windward side of such a thermal.
http://66.249.93.104/search?q=cache:_l9rvEHZ26gJ:www.wrcc.dri.edu/htmlfiles/westwinddir.html+%22wind+direction%22+san+diego&hl=en&ct=clnk&cd=23
    Only the cache version would open.  Scroll down to California and SD.

You might be interested in subscribing to this site:
http://www.iwindsurf.com/windandwhere.iws?regionID=138&regionProductID=2&timeoffset=0

Or following this one:
http://www.sailflow.com/windandwhere.iws?regionID=220