Our Volt and Bolt (and now the EQEV) were/are all parked outside all the time. I live in NH, and they've been subjected to freezing rain, etc, a lot.
I've only had one or two issues with stuck/frozen charging handles. A cover (or a charge handle boot) might have come in handy. Definitely go through a bit of fussing to get the charge door closed, too.
But those problems have been fairly easy to cure.
What I've actually had more trouble with (on the Bolt and the Volt) is prolonged torrential driving rain working its way past the charge port and (presumably) into the wiring behind it.
That rendered the Volt un-chargeable on several occasions, once for a couple of days. Sometimes it was the car that would refuse to charge, sometimes it was the L1 charger's GFCI breaker tripping repeatedly.
When it was the car that was doing the complaining, moving over to our L2 charger made no difference. 50-50 if it was a GFCI issue; our Hardwired ChargePoint would often refuse to charge as well. I'd say that pretty much means it was the car's problem most/all of the time.
Same thing with the Bolt, only with it, I'd learned some cures from our experience with the Volt. With both cars, I found that I could get them back to a happy state by blasting the connector and where it joins with the bodywork with high pressure compressed air. Sometimes needed to additionally hit it with a hair dryer for a while. That brought the cars back online every time.
I've found these problems to be pretty infrequent (maybe 5-6 occurrences over a ten year span), but it think I'll be getting a boot/cover/whatever for the winter, now that I know they exist and seem to be pretty inexpensive ;0)