ok all here is my set up, fits in a ziplock bag IN THE SADDLE bag.
first gear rain coat (thin water proof material) first gear rain pants, more thin material (but set up for motorcycling so the pants feel good and are comfy).
I have these large rubber gloves that roll up into a small bag, i would have to check the name, but there is a thumb and two 'spots' for two fingers each, when you wave you look like "VULCAN" symbol. Then for feet I have these things that go over the sole of the boot, and there is thin water proof material that goes under the first gear pants.
I have ridden like this in snow, monsoons, hurricanes and actually had somebody spraying me with a hose, never got anything wet except where it dripped down my neck.
note - the first gear stuff is also all retro reflective which is very good.