Wisconsin Fly Fishing for Trout

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.

See also: General Characteristics for Mayfly Species of Northern Wisconsin

Northern Wisconsin Mayfly Hatches

Common Name Scientific Name / Details Mar Apr May Jun Jul Aug Sep
Blue Wing Olives (BWO)(2) Baetis
size:6-7mm (#18 -#22)
nymphs 3 tails (middle tail shorter)
adults 2 tails
--XX XXXX XXXX XXXX     XXXX
Gray Drake Siphloplecton basale
size: 14-16 mm (#8)
nymphs 3 tails / duns 2 tails
  --X X--        
Hendrickson Ephemerella subvaria
size: 10-12 mm (#12)
nymphs 3 tails / duns 3 tails
  --XX XX--        
Sulphurs Ephemerella invaria / rotunda / excrucians
size: 9-10 mm (#14)
nymphs 3 tails / duns 3 tails
    --XX X---      
Sulphurs Ephemerella dorothea
size: 6-7 mm (#18)
nymphs 3 tails / duns 3 tails
    --XX XX---      
Small Blue-Winged Olive Attenella attenuata
size: 6-7 mm (#18) olive body
nymphs 3 tails / duns 3 tails
    --X XX---      
Black Quill Leptophlebia cupida
size: 10-11 mm (#12)
nymphs 3 tails / duns 3 tails
    --XX X---      
Gray Drake Siphlonurus alternatus
size 12 -16 mm (#8)
nymphs 3 tails
duns / spinners 2 tails
    --XX XX---      
Little Mahogany Paraleptophlebia mollis
size: 6-8 mm (#16-#18)
nymphs 3 tails / duns 2 tails
    ---X XX-      
Little Dark Hendrickson Ephemerella needhami
size: 9-10 mm (#14)
nymphs 3 tails / duns 3 tails
    ---X XX-      
Sulphur Epeorus vitreus
size 9 - 12 mm
nymphs 2 tails / duns 2 tails
    ---X XX-      
March Brown / Gray Fox Maccaffertium vicarium
(formerly Stenonema)
size 14-16 mm (#10 2x long)
nymphs 3 tails (clingers)
duns 2 tails (speckled wings)
    ---X XXX-      
Armored Speckled-Wing Baetisca laurentina
size 10-12 mm (#12)
nymphs 3 tails (fat body)
duns 2 tails (chubby mottled wing)
    ---X XXX-      
Light Cahill Stenacron / Maccaffertium
(several species)
size 9-1 mm (#12 2x long)
nymphs 3 tails (clingers)
duns 2 tails (speckled wings)
      XXX-      
Darth Vader Serratella deficiens
size: 4-5 mm (#20)
Blackish wings
pale yellow legs
nymphs 3 tails / duns 3 tails
      XXX-      
Brown Drake(1) Ephemera simulans
size 12-15 mm (#10 2x long)
nymphs 3 tails (burrower)
duns 3 tails (brown splotch wing)
      XXX-      
Hex Hatch
Michigan Caddis(1)
Hexagenia limbata
size 16-35 mm (#6)
nymphs 3 tails (burrower)
duns 3 tails
      --XX X---    
Mahogany Dun Isonychia bicolor
size 13-16 mm (#8 2x long)
nymphs 3 tails (swimmers)
duns 2 tails
      ---X XXXX XX--  
Tricos Tricorythodes minutus
3 -3 1/2 mm (#22 - #24)
nymphs 3 tails
adults 3 tails
        -XXX    
Large Rusty Spinner(1) Hexagenia atrocaudata
size 16-30 mm (#6)
nymphs 3 tails (burrower)
duns 3 tails
        --XX X---  
Little Yellow Quill Leucrocuta hebe
size 9-12 mm (#12)
duns 2 tails
duns yellow body & orange thorax
        ---X XXX-  
White Mayfly(1) Ephoron leukon
size 10-13 mm (#12)
nymphs 3 tails (burrowers)
duns 2 tails (white body)
          XXX-  
Common Name Scientific Name / Details Mar Apr May Jun Jul Aug Sep

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 Caddisfly Hatches (Sedge)

Below is a listing of the most common Northen Wisconsin caddisflies that are found in our freestone streams that may have importance to fly fishermen in different stages of their lifecycle.

  • Little Black Caddis
  • Little Short-Horn Sedge
  • American Grannom
  • Spotted Sedge
  • Green Sedge (Green Rock Worm / Apple Caddis)
  • Little Sister Sedge
  • Long-Horned Sedge
  • Little Plain Brown Sedge
  • Zebra Caddis
  • White Miller
  • Giant Rusty Sedge
  • Great Brown Autumn Sedge (large stick cases)
  • Little Dot-Winged Sedge

See also: Lifecycle of Caddisflies for more detailed information.


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Page Reviews
Web Page: Northern Wisconsin Trout Stream Mayfly Hatch Chart
by
Overall Rating: 5.0 stars - 5 reviews

Paged Reviewed: Northern Wisconsin Trout Stream Mayfly Hatch Chart
Reviewed By: Joe Hawkins
Page Rating: 5.0
Review Date: 16 May 2012
Page Review:
This is great mayfly hatch chart!! Thank you WiFlyfisher!
Paged Reviewed: Northern Wisconsin Trout Stream Mayfly Hatch Chart
Reviewed By: B Towle
Page Rating: 5.0
Review Date: 3 January 2014
Page Review:
This is extremely helpful. I'm hoping to get started on fly fishing for trout in NW WI and this will help greatly.
Paged Reviewed: Northern Wisconsin Trout Stream Mayfly Hatch Chart
Reviewed By: Matt
Page Rating: 5.0
Review Date: 15 February 2014
Page Review:
Overall a very nice presentation of the Wisconsin mayflies. BTW the East Branch of the Delaware has a very intense emergence of simulans in early June for about two weeks. Huge rafts of duns come down river. In the beginning the big browns are gluttons but soon become wise to patterns that don't look very good or have drag in the cast.
Paged Reviewed: Northern Wisconsin Trout Stream Mayfly Hatch Chart
Reviewed By: Jim S
Page Rating: 5.0
Review Date: 29 December 2015
Page Review:
Great hatch chart. Appreciate it.
Paged Reviewed: Northern Wisconsin Trout Stream Mayfly Hatch Chart
Reviewed By: Bob B
Page Rating: 5.0
Review Date: 27 March 2019
Page Review:
Great website, very informative.
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