The famous nocturnal Hex hatch of the Midwest (and a few other lucky locations) stirs to the surface mythically large brown trout that only touch streamers for the rest of the year.
A trout, and steelhead guide for many years in the Seattle, WA area. I've taught fly fishing schools for 30 yrs., and was the fly fishing technical advisor, and worked many days on the set for the very popular tv show, Northern Exposure.