Not remotely true. California has a unique combination in some parts of the state of mild temperatures combined with low precipitation. Other places with mild temperatures tend to be much, much wetter. Other places with dry weather tend to have more extreme temperatures.

Off the top of my head:

The joke is that San Diego is "72 degrees and sunny" year round. San Diego gets about 10 inches of rain annually. Fresno gets 11 inches. SFBA gets around 20. Average for the nation is 44 inches annually iirc.

If you go someplace dry that's more inland, it's typically blazing hot in summer at a minimum and deserts can have temperature swings between day and night of 30 degrees or more.

I agree the weather's awesome in CA, but it's also pretty fine in AZ, NM, TX, MS, AL, LA, GA and FL. Is there evidence of mass migrations of homeless people to CA from the rest of the U.S.?

Why wouldn't the housing affordability problem in CA be directly contributing to homelessness there?

I have seen articles indicating some states have been known to stick people on a bus and ship them to California.

I run several homeless sites and routinely read r/homeless. A common question is "Where can I go with better weather than where I am currently?"

I spent several years homeless. I was evicted from my apartment in Georgia and walked and accepted rides to cross the country to get back to California. So I basically camped my way across the country.

I'm quite confident I know whereof I speak on this specific detail.

Though just to be clear, I am not suggesting we ship all our homeless there, though it absolutely is true that some portion of the homeless population in California traveled there from elsewhere in some fashion.

The weather in TX is better described as miserably hot in the summer. We don't have the stabilizing influence of an ocean right next door (the Gulf doesn't really help except right at the coast).