I’vehad mine for a year and gone 15,000 miles.
It seems to do well in the heat and poorly in the cool and I’ve never had mine colder than 40 degrees.
According to the in car display, 90 degrees OUTSIDE temperature is ideal. Even at 85 degrees my driving “score” is starting to get lower.
So 90 degrees is not a maximum, just anything above (and apparently below) this is less than ideal.
Range is down significantly as soon as the 50’s.
But I’d think the battery would be “healthy” at 50, just not drive as far.
Many years ago I looked at racing electric vehicles with lithium batteries and just like you smoke the tires to heat them and make them stickier, you want your battery as hot as 150 degrees F to get the maximum power out of it.
Now maxiumum power and maximum life are very different things: race cars don’t expect to go 100,000 miles on the same battery. But it illustrates they tolerate heat very well.