I fly FPV drones a lot in the winter where it is wet and snowy. What is the best way to protect your equipment from shorting out from water?
The first step I take to help protect my gear from shorting out from water is to apply silicone conformal coating to all the electronics I can. I cover the ESC, flight controller, vtx, and any other exposed electronics. I find that this also provides some protection from random solder drips or conductive grains of sand.
However you have to be very careful because conformal coating will block electrical signals that you want to work, like your USB port. Also don't coat the barometer if you FC has one.
What other tips do people have for protecting their gear from bad weather?
As mentioned a conformal coating is what you need. There are various types and methods of application. I haven't personally used this product, but it does look like the best and easiest:
Other options are more standard electronic conformal coats which you apply with a brush or spray (hint: spray gets really messy, get the brush type). I've used two different ones but don't have links to either any more unfortunately.
One is a bit like nail polish. Dries quickly and works well but stinks like anything when you solder through it, and dissolves with isopropyl alcohol (which may be good or not depending on your application).
The other took a lot longer to dry and required a UV cure (think: leave it in the sun) and was basically vastly superior. It was easy and less messy to solder through and was much, much tougher. I used this to fly in snow and even through sprinklers once, just for fun.
If you're using either of these, just apply carefully and as thinly as possible with the little brush. Avoid clogging the usb port, micro jst connectors and barometer if you have one. Do the boards before soldering, leaving the pads clean, then after attaching all the wires touch up the final parts.
Most conformal coats have a nifty feature where they glow in UV light, so you can easily spot any missed areas.
ImmersionRC conformal coat their electronics at the factory, so if you have a Vortex or Tramp vtx chances are it's already waterproof.
Note that you only need to do electronics, motors are intrinsically waterproof. Cameras are tricky and not as well sealed as you might think, but for things like snow and rain you'll be ok. Total immersion in water is another thing entirely. Fresh water you can get away with, but seawater is a death sentence, sooner or later it will be toast.