September can be a great month for fly fishing and comparable to spring fishing in some respects. Fly anglers will welcome the return of decent hatches of the Large Dark Olive. This upwing fly is a firm favorite of trout and grayling and can provide some wonderful dry fly fishing through September.
Both the nymph and the dun are worth imitating, the spinner which lays her eggs underwater and also the male spinner can be pretty much ignored as the rarely present themselves to the fish. The large dark olive can be one of the best flies for fly fishing in September and it’s essential to have some patterns ready to go.