What metro is it and does the dedicated bike infrastructure get plowed and otherwise well maintained in the winter? Oulu's record low is < -40C and they don't observe much of a decrease in cycling until around -20C.

Hot days aren't an issue for ebikes until you get to extreme temperatures. I've found it to be much better than walking; I'd sweat more waiting for my car to cool down. This is in Sydney, up to 40C and fairly humid.