A specific example. For the Tesla Model 3 battery temps between 15 and 35 Celsius are considered optimal. Tippy top Ideal is probably 20-30C. But either way... Negligible physical degradation. Outside of that. Yes - Range can be affected. How much matters though. Of course... It depends on how far outside that range you go. And for how long. Where I live. Fully two thirds of the year it will be a rare day indeed where the ambient temperature is NOT within the optimal range.
Extreme temperature can affect battery life. But then we're talking about like 40C+, which could cause minor degradation if experienced for a long time. Or even 50C+ which can be substantially deleterious - Again, if experienced for a long time.
Here's the thing though... It only matters while an EV is not in operation. AND not plugged in. AND only once the seriously insulated battery packs have finally internally equalized with the ambient temperature. The rest of the time the BMS will work to maintain near ideal temperatures. Which will affect range, yes, but at least the battery will be safe. And the range impact is also much less than letting the cells operate outside of optimal ranges. The gold standard these days are heat pumps. You get a lot of cooling/heating for relatively little energy. Since you're moving heat around. As opposed to heating systems where heat is outright generated.
Where temperature and range is concerned... Extreme cold is much more problematic. Yet many EVs now do quite well even in very cold climates.
Literally the only notable troublesome scenarios, are ones where EVs remain unused, and unplugged, for lengthy periods of time. During which it also happens to be seriously hot. Not just very warm. Hot-hot. Most places in SA - No problem.
Moral of the story. Don't leave your EV standing outside, unused, unplugged for the entire summer, in like... The Karoo. That's just looking for trouble. Of course if you do leave your EV stowed in a garage in the Karoo all summer. And the garage rarely gets hotter inside than 35C. Again - No problem.