We've heard various predictions before, but a new study based on climate-change models as they would stand today (assuming nothing more is done to curb emissions and temperatures continue to fluctuate as they have) says that SF is on track to become the most comfortable of all major cities, temperature-wise a title currently held by San Diego.
The study, which the Washington Post just picked up via the latest issue of the journal Scientific Reports, looks at 25 major cities across the country and projects, under one model, what their temperatures will look like throughout the year based on this as-is climate-change model. The study was executed by climate scientist Ken Caldeira of Stanford University’s Carnegie Institute of Science and an intern in his lab, Yana Petri, and it looked at the number of days cities spend above or below 65 degrees, which was used as the measure for the number of days that would potentially require some type of heating or cooling.
Anyway, the methodology gets complicated, but suffice it to say New York is only going to get hotter, and require less heating in the winter, Minneapolis is going to remain one of the coldest and sweatiest places in the country as it is now, and while there will be a movement toward things being more temperate overall, San Francisco may just win, with Los Angeles and points south becoming more like Jacksonville, Florida.
Sorry, SoCal. Anyway, the model is looking at the years 2080-2099, and Caldeira warns that this is merely one prediction model.
Also, it should be noted that this study only looked at temperature, and there are other factors that need to be considered too, including cloud cover and precipitation. Having San Diego temperatures won't be that awesome if it's muggy and cloudy all the time, with monsoons all summer, as I'm sure you'd agree.
Related: Bay Area, Pacific Northwest Should Be Just Swell After Climate Change