Northern Wisconsin Trout Stream Mayfly Hatch Chart

Below are listed the most common Wisconsin mayfly hatches created by John Simonson (WiFlyFisher). This is mainly for the northwest Wisconsin and central Wisconsin trout streams, such as: the Namekagon River, Bois Brule, Prairie, Wolf, etc.).

The X's represent individual weeks within a given month and the approximate emergence time for each mayfly. The hatch dates will vary from year to year depending on the weather conditions, seasonal climate changes, type of stream, etc.

Northern Wisconsin Mayfly Hatches

Notes:
(1) - indicates mayfly nymphs that burrow in sand, silt and muck. The densest hatches for these insects will occur in those stretches of the stream.

(2) - there are several mayflies species that all fall under Blue Wing Olives (BWO) and hatch at different times during the season. Some I see are too sporatic to really get the trout's attention.

See also: General Characteristics for Mayfly Species of Northern Wisconsin

Northern Wisconsin Trout Stream Caddis Hatches (Sedge)

I don't know the scientific names for most of the dominant caddisfly hatches, but do not under-estimate the importance of these little fluttering critters. On many of the Wisconsin freestone streams that I frequently fly fish for trout there are numerous caddisfly hatches that trigger heavy trout feeding. Some of my favorite caddisfly hatches are the Grannom (Brachycentrus), Green Sedge (Rhyacophilia), Dark Green Sedge (?), Little Black Sedge (Chimarra), Spotted Sedge (Hydropsyche), Ginger Sedge (?) and Great Brown Sedge (Pycnopsyche). You can find caddis on the rivers pretty much all summer long from East Coast to the West Coast. I prefer tightly wrapped wool for the larva stage, Gary LaFontaine's Emergent Sparkle Pupa or a small bead head, gold-ribbed hare's ear for the emerging caddis, and elk hair caddis, or diving bead head caddis for the adults. See the Caddisfly page for more information.