My first instinct was to simply reply "ummm, no."
However, I know people's comfort levels are different, so I went to Weather.com to see what the averages are. Since you are going in early June, I thought I'd give you the May and June averages. May average highs are 75, June average high is 79. Even April's average high is 73, so there will be at least a couple months of pretty wam weather to heat the pools (more than the heating the motors provide) and a good chance of upper 70's temperature.
I understand where the San Fran people are coming from though, honestly, June would be a hit or miss for swimming up there. We went in August one year from Sacramento. In Sac. it was 88 degrees...so very hot. We went down to the pier in San Fran and had to buy sweatshirts, I kid you not, it was so cold. And damp. So. Cal. doesn't have the same vagaries of temperature that the Bay area has, so you should be just fine.