The most widely available 0W30 at most auto part stores and WM is M1 0W30. GC 0W30 is hard to find, most other 0W30 oils are available by mail order only or at specialty auto part stores.
Exxon/Mobil dominates over the counter 0Wxx oils, from 0W20 to 0W40.
at least the Mobil AFE 0w30 has better low temp. pumping than PZ synthetic 5w20.
Mobil 1 AFE 0w30 MRV at -40C 11,100 PZ 5w20 MRV at -35C 9,700
I had been wondering about those two specific oils, as I have some of both in my stash. I'm still learning what all of the statistics mean, but am I to gather from this that the Mobil 0w30 would be a better cold-weather fill than PP 5w20, from a protection at cold start perspective?