Lunch at "Bar-B-Que House" Ocean Beach (yelp link).

View from the pier at Ocean Beach, San Diego:

Tried the water, but it was a bit too cold for swimming.  Still a few surfers in wetsuits and little kids who don't care about the cold.

24-hour water temperatures:

1-year water temperatures:
This data is much noisier than I expected, but it appears that only July through September have >=70 degree ocean water temperatures.