Depending, of course, on where in the country you are and what kind of airfield you fly from, you may be surprised at how much flying you can get done in winter.
I find the mixed weather in Autumn and Spring cost me more hours than mid-winter itself; all of my milestone flights (first solo, QXC & test) were in the winter months so I must have been flying enough to keep momentum up.
I would make plenty of bookings, accept that some will be lost, and push on. That said, it does no harm to keep up with the exams too, keep you busy during the dark evenings
