Nothing is worse than shooting in the rain, snow or sleet. But like the Post Office we must deliver. Here is how I protect my gear:
I own a Motu Sound Slick which is a large poncho well made with a clear area allow you to see your bag to mix it works well but is large and hard to carry around. But it works well and I have been in gail force winds with heavy rain and wind, and it kept me and my gear dry it also allows you to protect your boompole as well. , however if time permits I like to add a 2nd level of protection.
I usually wear a rain suit under my sound poncho or just the rain suit pants since your legs can still get damp. It will also help keep you warm in cold wet weather.
If the weather looks clear for the day I will leave all the rain gear at home. I always keep a $0.99 emergency poncho inside my sound bag in the event of an unexpected shower I can cover myself quickly. With this rain gear you and your gear should stay dry!!!!