Most tourists are surprised to find that San Francisco really isn't all that warm. Our summers are gloomy and the fog+wind rolls in right at 5pm nearly everyday. We really only get about 1 month of warmth(I'm talking 70-80 degrees max) a year and September is it. We are just now getting into our tomato season whereas in most places throughout the country, summer fruits and vegetables are over and done with.
I find that tomatoes are best when they're just barely tampered with. a little salt is all you need. I put them atop wheat toast nearly every morning with a slather of good mayo. Simplicity at its best.