Where can I live with a convenient public transportation system?

I currently reside in Southern California, and I love the weather here. I am not very good with cold climates. My only issue is my strong dislike of driving. So Cal is not convenient, even in the bigger cities, in terms of m transportation. I have traveled to San Francisco, London, and Tokyo, and really enjoyed the train/metro/subway systems. If I were to live somewhere in the U.S. or Canada, or even globally, where do you recommend? San Francisco and London were a little too rainy, chilly, and gloomy for me. Is there somewhere like So Cal in terms of weather and sun, but with an upgraded and convenient transportation system?