Let me speak out of both sides of my mouth. On the one hand, things like the slides get hot in direct sunlight. However, I have clambered all over these sets in some nasty hot weather and don’t remember the vinyl as hot. That could be because you really don’t come in contact with the vinyl very much during play. Regardless, if the vinyl is too hot, I can guarantee it is too hot to play outside safely.
Vinyl swing sets handle heat very well compared to metal swing sets. Some of us remember going down those metal slides on a summer day…