Rotella T6 OK for winter?

[Erilflynn]

Just finished my first season with synthetic Rotella T6 5-40 and it's time for my winter oil change. Wondering if there is any need to change over to an oil with a higher viscosity i.e. 15-40 (such as Triple T) or 10-40 for the winter? I live in NJ so temps occasionally can hit single digits overnight and I keep my Nad in a shed with a battery tender. And I still ride throughout the winter when I can and the temps are over 35F. Thanks in advance.