0w-20 vs. 5w-20?
There's no benefit to using the 0w-20 in hotter climates like SoCal, South Texas, Gulf Coast and Florida, etc. In fact, the 5w-20 would probably offer better protection year round. Maybe the engine wouldn't notice the difference until 200K, 300K, or more miles. Doesn't really matter. There's no reason to use a 0w-20 in those hotter climates. One size isn't optimal for all environments.