The week after Labor Day is my least favorite week to fish in the Park over the entire course of the season. Everybody who wants to fish without the crowds comes then. Anymore, the anglers don't really go away until the last week of the month, if not early October. If you can hike, you can get away from people, but the roadside streams will be as crowded as they are in July, with less water to go around.

The Yellowstone outside the park is generally much less crowded than the Park rivers by September, I suspect because more of the September anglers go without guides and thus there's less drifters out. We still stay quite busy. In fact, I ran more trips in September this year than July, though that was partially a result of more special request bookings.

The fishing is much more consistent in July than it is in September. Not saying it can't be good in September, but it's much more hit-or-miss. If you have good waters levels and have a cool, drizzly day with lots of Baetis, it's epic. If it's hot and bright and the water's low, it can be awful. The last couple years have kept the fishing good on the Yellowstone in early September, but given the snowpack outlook I suspect next year it may be tougher until later in the month when the light is flatter. Late July is usually at least decent. The only exceptions are years of extreme drought like 2007. If we have at least a 75% snowpack, the fishing typically stays consistent through July (2007 it was 50% followed by a hot, dry summer). I've been here since 2001 and 2007 was the only year the fishing wasn't still good in late July, though several years it was tough by the first week of August.

The trip planner at www.parksflyshop.com has tons of information on flies, where to fish, what to bring, etc. etc. www.parksflyshop.com/planner.htm