During the day wouldn’t be ideal either, but it’s dark at 5pm there. If they wanted it for the lights they could run it in the dark 4-5 hours earlier when the US could watch, but that would then make it an inconvenient time for the european viewers, which have clearly been made the priority

Edit: Also the temperatures aren’t a concern. It’ll be 20C air temp high this week. There’s no heat concerns, and anyone who’s saying there is has no idea what they’re talking about.