In America they 'preheat' and use the correct grade to suit time of year.
Yup, and in Canada even more so (unless Canada is "America" for this purpose
).
If the oil is too thick to start, it, and the engine, are too cold to be started - preheat both of them!
My O-200 specifies 80 weight oil, so that's whats in it year 'round. If colder than +5C, I'll preheat with an engine blanket. Down to -25C has never been a problem for the O-200. Colder than that, I rethink needing to fly. Though my record was ferrying a 172 from central Quebec, when the temperature at departure was -40.