The Famed Hex Hatch

Hexagenia limbata - The Hex

It's coming soon to a stream near you!

...or not

Southeast Pennsylvania may not have a hex hatch - you may not have even heard of the hex fly.

Hex is short for Hexagenia limbata. It's a fly known for its major hatch in the midwest. It hatches late at night between June and September. The large hatches most know usually occur in late June and early May. Because the hex are so large, they almost always bring large brown trout to the surface. This makes the hex hatch a prime time to catch fish and it brings tons of fishermen to streams.

Some hatches are so large that they appear on

Radar image showing hex hatch on Mississippi River

radar. In the radar image to the right, on May 30. 2010, the hex hatch on the Mississippi River was so dense that the waves produced by radar bounced off the flies and went back to the radar.

Each year around the Fourth of July, I take a trip to the AuSable River in Northern Michigan, just after the hex hatch is over. My father used to go out at night and trick a few trout on a hex about a week afterwards. Sometimes he'd catch a few nice brown trout.

It's an amazing feeling when these giant mayflies are all in the air and landing on your arm, your rod, reel, and everything around you. So, it should be on your bucket list to go to a midwestern stream and experience the hatch for yourself.

Summer Heat is Just About Here

It is almost unbelievable that there are trout streams in southeastern Pennsylvania, so close to downtown Philadelphia. But there are downsides...

As we head into the latter part of June, temperatures definitely start rising. And with that comes warmer water temperatures too. Some streams can get into the 70s. This is not good for trout, and then the smallmouths and panfish take over. In mid-June of 2014, our first heat wave had air temperatures in the 90s, and we will soon see water temperatures over 70 in many streams.

Once June arrives, many large fly hatches are over; the cream cahills and slate drakes hatch in early to mid June. You'll have to wait until August for the next big hatch: Trico.

July is probably the lowest point in trout fishing for southeastern Pennsylvanians. Most trout have died off after the warm water temperatures and fly hatches are mainly over. There many be a few holdover trout, but they are struggling to hold on.

So if you're heading out to a stream in Southeastern Pennsylvania, beware, the fish, the flies, and the water, is changing.