I've done it in Vermont USA in the summer with all windows closed.
Infrared saunas are 120-140f.
https://www.saunasociety.org/sauna-experience
A car reaches 120f on a 70f day in the sun in 90 minutes so I don't think that temperature would damage that many things.
https://www.scottsfortcollinsauto.com/how-hot-do-cars-get-in...
This company selling electric bed bug heaters says 7 minutes at 115f.