I've flown other 3DR drones in winter, including at -10 degrees. Some pointers:
Battery life is reduced. Keep them warm before using them. Putting them in your jacket works if it's not too cold, but keeping them in an insulated bag with hand warmers is much better. If your not hiking/snowshoeing away from roads, consider keeping your spare batteries in a warm running car.
Leave your drone out in the cold for awhile before attempting to take off. The barometers are very sensitive to moisture, which you can get if you move your drone from a warm car into the cold (condensation frost). If it's very cold (say below 10 degrees) you might want to wait as long as 15 or 20 minutes before powering up. If it's a "dry" cold, this is less of an issue.
Pick a good take off spot where your not likely to kick up snow that will get in your motors. Take off from ice, or at least stomp down an area of tightly packed snow.
Snow landings are soft and rarely lead to damage, but if you get snow in the motors, do this: immediately blow as much snow out as you can BEFORE you go into a warm area where the snow will melt. Compressed air is best, but blowing really hard yourself is better than nothing. If it's very cold (i.e. the snow isn't wet and clumpy) this is pretty easy. When you go inside use a blow dryer to dry out the motors and anywhere else snow got in. I often place my drone over or near a warm air vent (rotating every few hours) to make sure everything is dry.
Do NOT fly through fog or clouds. You can get icing on your props which will often lead to a crash, or at the very least, extremely difficult flying.
Don't fly when it's snowing. Actually, flying when it's snowing is not that bad, as long as it's not a wet snow. Nonetheless, I can't recommend you do it. I have many times - but only when it's below zero. Maybe I've just been lucky.
Use an ND filter to help cut down on the bright reflections off the snow. I use anything between an ND8 and ND32 - although I've gotten good images with no filter at all.
There are RC Controller mittens that you put the entire controller inside. I don't use them anymore. I just wear warm mittens with glove liners that are electrostatic so I can whip off my mittens if I need to and use the touch screen with the liners.
As soon as it starts snowing, drop everything and prep your drone. Footage after a fresh snowfall is amazing (in my opinion), especially while snow is still clumped in trees.
That's all I can think of for now. Hope it helps.