Over here, the pumps say additives added to be good to five degrees or some such, I see too many big rigs stalled along the road and the service truck setting there with the mechanics changing fuel filters. something I will avoid at all costs. LOLMost suppliers gauge the weather and blend to keep fuel from gelling. Never hurts to add a little for your own peace of mind. For lubricity, B5 to B20 blends like we have in Illinois are good but again, another additive of your choice sure wont hurt.