Getting through the cooler months while staying fit is all about being consistent. Stick to a schedule. Lay out your weeks worth of training on the weekend and stick to it.

IT DOESN’T HAVE TO BE THAT WAY
I often hear people accepting the “fact” that winter is the time they / people in general put on weight.
Winter can actually be the best time to lose weight and train harder.
– One thing that limits you from pushing during the warmer months is the simple fact that your core temperature gets too high and your body stops you from continuing.
– Being cold isn’t a bad thing. Thing of your bodies temperature like a fire. It has to stay at 37.5 degrees. To keep this consistent your body has to fuel the fire. Yep the same fuel you eat and burn while training or living day to day can be burned so as to keep your bodies 37.5 degree temp maintained.
– Less sweet fruits. The all the sweet sugary fruits that come out in the summer months are no longer in season. So your likelihood of consuming lots of sugar (although natural) is decreased.
– Weekends are generally less busy and more consistent. Often peoples food prep and weekly planning can have its hurdles with weekends spent beaching / day tripping or with weddings and christmas parties.