Like many ETS'rs I suppose I overcompensate. I have umbrellas in each car, full rain suits in each, a spare rain jacket in my car and a GoLite Hiking Umbrella in a pouch on my workbag. The latter is really compact and lighweight. It will fit nicely into a jacket pocket or briefcase. I keep an Aloksak bag in my cell phone case to protect the phone. I also have SealLine protective cases for my e-reader, my Ham HT and one for my GPS.

Oh, and I keep a throwaway plastic poncho in my briefcase as well.

But usually I just run for the door from the car...