I had seen it advertised elsewhere, but it wasn't available when I needed it.
I did a search, and found the Village Hat Shop ... with the same hat, top brand, for less than the other places, and in stock! One of my best finds ever.
Over 3 hours of standing in a moderate rain, with temperatures in the upper 30s, and this hat kept my head dry and warm.
(Mine has a small wooden slider on the chin strap, which worked fine for me; perhaps it wouldn't hold under a heavy wind, though.)