- Hands get very cold on sticks quite quickly when it's snowy. Thin cycling gloves are a good compromise between stick feel and warmth, or you can get proper 'transmitter gloves'.
- Put your batteries in your pockets to keep them warm (mitigates the shorter flight times you get in the cold).
- Take sunglasses with you - if the sun is out, there will be nowhere to look that isn't too bright if you forget them !
- Use a landing pad so you don't flick wet snow up into your gimbal on launch / landing
- Be extra careful what you are standing on as you move about. Don't want to be falling over holding that controller...
- Enjoy the relatively rare situation where the sky is roughly the same exposure as the ground !
Agree with all of that except for the fogging. A cold lens will fog when brought into a warm room. A warm lens taken outside into the cold will not fog.
If it's snowing you may want to find a place to keep the ST16 dry. Once the screen gets wet the touchscreen functions won't work. I cut the fingertip off of one glove to fly when it gets really cold. As AeroJ points out, your hands will freeze holding the controller. Don't try to do any precision flying in cold weather. It's much more cumbersome to maneuver and things may feel sluggish so stay well away from any obstacles. Expect flight times around 10 min even with warm batteries.