Around here we don't consider 50F to be cold. Many/most of my summer rides are done around that temperature.

Back on track: I don't alter my water consumption much as the temperatures alter between 85F and 35F. My limiting factor is generally my ability to keep swallowing and get the fluid absorbed, not how hydrated I am. The only difference is how dehydrated I get per hour.

When I'm riding in a place where it is warm, like up to 110F, I make a point of drinking more, but I know at some point I will dry out unless I really force the issue by cutting back my output in order to allow some blood flow to the gut.