SF Bay Area weather is pleasant year-round (not too hot in the summer and not too cold in the winter), has low humidity and low rainfall, and is sunny on most days of the year.
What other areas in the US, if any, have similar climate?
You might investigate San Diego.
Pretty much every point in between San Diego and SF along the coast. It gets a little warmer and a little drier as you go south but not that much.
Nice year round weather is pretty rare. I read somewhere that there are only 3 Mediterranean climates on the planet. The west coast of California, the Mediterranean, and the Indian Ocean side of South Africa.
Eureka? Bodega Bay? 
I thought there were a few more, and it turns out, its only a couple more.
I was just going to say I thought Australia had some of that … thanks for the link.
Granted, but are there any locations in the US, other than California, that come close?
It would be a bit strange if in the vast expanse of the continental US, there was no other location with pleasant weather (low humidity, no extremes of heat or cold, etc)
Strange why?
Doesn’t the bordering Pacific Ocean make that area extremely unique, as the kids say?
If you look at the wiki link form Great Dave you will notice that all the places border the ocean. Certainly in southern California once you get away from the ocean the temperature variation starts to go up a lot. It gets hot in the summer and cold in the winter.
Your thought process intrigues me. Take a look at a U.S. map and give us a rough area where we might find these places.
Using a broad brush:
South = hot and humid much of the year
Southwest = hot and dry plus some cold
New England = 4 seasons that cycle from very cold to hot
Mid-Atlantic including New York = Similar to New England
Midwest = very hot and very cold
There just aren’t any other places in the U.S. with very consistent weather and no extremes. The best you might hope for is to find a couple of months in say, Florida where it isn’t too hot and yet the Atlantic keeps the temperature in a nice range. Other than that, the rest of the U.S. has real weather with lots of extremes.
Now that one depends a lot on where you live in the city. SF ( and the Bay Area in general, but SF is a microcosm for this sort of thing ) has a crazy number of microclimates and my old place in the Sunset District, three blocks from the beach, was definitely NOT sunny most days of the year.
Which is fine with me, I like overcast and misty. But much of San Francisco is not a warm city much of the year.
I guess that’s why houses here in the Bay Area cost 5 billion dollars 
(talking about “the City”)
Well, yeah. Marin County, San Diego, the coastal sections of LA have some of the best climate in the world. It would be amazing if their house prices were normal. Everybody wants to live there, and those who can’t want to live close to what those places provide, which is why people live in the 100 degree valleys around L.A. and commute 90 minutes in.
And why the same money that buys used a decayed mobile home in those areas of California would buy a 22-room mansion in Upstate New York.
Thanks for the link! My sister lives in San Diego and every summer I call her from Dallas, TX and say: “Can I come live with youuuuuuu?” But I don’t think I would survive financially.
So now I know where to focus my efforts of finding a similar climate that might not be quite so expensive.
I’m very big on living in an area with good weather, because it has such a big impact on your day-to-day quality of life. However, I think that the quality of the house you live in also impacts your quality of life.
At some point on the scale, living in a nice-enough house/mansion in crappy weather will outweigh the the benefits of living in a crappy house in good weather.
This is all very real to me right now, as I am contemplating buying a house in the Bay Area, but, looking at what you get, for the amount of money you spend, I can’t help to think there may be locations in the US where (for a given amount of money) the quality-of-house-vs-quality-of-weather tradeoff is better than in the Bay Area.
It sucks having to pay 1.5 million dollars for a small, old, house. You live in it, sleep in it, wake up in it, and spend a good percent of your life in it, and it adversely impacts your quality of life if you don’t like your house.
On the other hand, I hate having to go out in -20 degree weather, or having to go out when it is hot and humid and you sweat like a pig.
Of course, I could get a house a bit further out from the Bay Area and get more reasonable prices, but then I would not want to commute 3 hours every day.
I thought there may be some locations in the US where the weather is reasonably nice, and the house prices not insane.
We save it on air conditioning bills. 
In my neighborhood (not Palo Alto, but pretty good) 3 bedrooms are going for between $600K and $700K, according to the real estate people. I’m between 30 and 60 minutes from the heart of Silicon Valley, depending on the traffic, and closer to lots of companies. Our house would be about $800K now, maybe a bit more, but it’s a five bedroom and reasonably big. So, don’t panic.