Here are two excerpts from the owners manual of a 2013 and a 2014 Chevy Silverado. In 2013 Chevy recommended 5w30 but if ambient temps went down to -20 F, they recommended using a 0w30. In 2014 the 5.3 and 6.2 V-8’s were redesigned and they went to 0w20 for year round use. This may have been due to CAFE or whatever, but they were not afraid to spec a 0w for year round use.
Going back to 2013, they thought -20 F was a good time to switch to 0w. Anything above that, the differences are small. I am running 0w30 in my Burb, but I will see a few -20 F starts after cold soaking all afternoon sometime during this winter.