Summer is actually a time when I feel a bit better. I have less suicidal thoughts due to sun rays, sunbathing, swimming. And I don't need to wear multiple layers of clothing, I just can throw on a light summer dress and go out. I think moving to Southern Europe would help me a lot, living in Northern Europe can be really depressing.
But I understand that there are people who absolutely can't stand the summer for many reasons. A good idea would be to move somewhere North.
But for a homeless person it's better to be somewhere warm. It's not ideal of course. But damn, last winter was so cold where I live, I know some homeless people who suffered horribly - got frostbites, gangrene, one man cut off his toes with a knife because his feet were gangrenous and the hospital didn't want to let him in. Another poor man died horribly sheltering himself from the wind, snow and extreme cold.