Naturally weather resistant material?

What do you mean by natural? Do you mean a non-"synthetic" product, eg wool? Depending on weave, thickness, denier, wool could come into that category. Felted wool can be quite weather resistant.

Sorry, I meant something that doesn't rely on DWR or another coating that can easy come off.

Perhaps search for some of Richard's data on here with measurements of CFM. Breathe a small bit, shed water/rain/wind…that sounds like lots of fabrics.

There was wax and oil, of course it smells like a fishing shack, but I just did a blow through the fabric test on my old oilskin coat and my DWR coated wind shirt (MEC RD) and taking in consideration the thickness of the material I'd say they're about the same.

Not a lab test, but fairly amusing for a few moments ;)

I'm also in for info on a material that is WR without coatings. Who's got info?

Old school wool. Look at Pendleton and Filson to start.

wool – heavy – especially when wet – give up BPL membership…

Ventile cotton apparently fits the bill. Long staple, densely woven cotton, with a weight of 230 gpm and a hydrostatic head of 750mm. I suppose light leaves a little to be desired, but there's no coating to wear off, and it's a lot lighter than waxed canvas.

Actually, waxed canvas has a coating that wears off, and is a real pain to reapply.

I guess the old Epic used to be a thing but the current stuff is not as good anymore and you can't buy it.