Lived in Key West for two years, and Miami for three. I spent about 3 years in San Diego, specifically PB about 5 blocks from the ocean. That's my points of reference.

The Keys have perfect weather for three months (the winter), but it gets pretty dang hot during the summer months. The humidity in South Florida is brutal.

San Diego's temps were three degrees cooler than LA in the summer, and three degrees warmer than LA during the winter. If you lived near the ocean, air conditioning was not required. You just opened your windows. San Diego has very low humidity, while Florida has very high humidity.

Temps were really nice near the ocean, but they climbed as you drove east up into the desert. I think San Diego's weather is the best in the world. Better than the Mediterranean, and better than anywhere in the US.