Homeless people often go where the weather is tolerable. Many homeless people prefer to camp outside rather than stay in the shelter system. California is the overall best state to camp outside long-term and year-round.

It then becomes a recipe for remaining homeless because the housing is so expensive. It's easy to camp out, not easy to afford rent.

If you can't afford housing anywhere in the US, going someplace you can camp reasonably comfortably makes sense. Remaining someplace with worse weather doesn't automatically cure whatever other issues are contributing to your intractable poverty.