zdnet[.]com/article/using-your-iphone-in-high-temperatures-can-cause-permanent-damage-heres-how-to-avoid-that/
Today it's going up to 91 F here in the Midwest US, & all my sympathies for those in the EU & UK with temps over 100 -- been there, done that when we lived in Arizona, and it wasn't fun, even when we were used to high temps. However, the electronics & rechargeable batteries in your phones and other gadgets like such high temps even less than you do. Apple & Samsung say their devices should be used with ambient temperatures between 32 & 95 degrees F. If/when it's hotter than that, don't, unless it's an emergency. And in that case, taking them out of the case, if you use one, might help.
