Winter Fishing Report

By Dan Pass - December 28, 2021

Winter is finally here, temps in the high 30's for the most part, a few days will hit into low 40's. Water flow on both river are around 450cfs.  Despite cold weather and lower flows, we all know this can be the best time to be on the river!  Less competition, more solitude and hungry fish can make for a great day fishing.  Dress appropriately, bring some hot cocoa and head out!  This fishing report can be applied to both the Big Horn River in Thermopolis and North Platte river from Miracle Mile to Grey Reef.

Sow bugs are the ticket later December through January/February.  They work year round, but they actually reproduce in January so the larger females and the smaller males connect to each other similar to other bugs when they mate, thus larger fuzzy sow bugs can really get a trouts attention.  I use up to a size 10 believe it or not! But a selection of sow bugs from 14-20 is perfect.  Grey seems to be the best color but tan also works.  Sometimes when I tie the big “connected” bugs I’ll use Grey for the larger and put a piece of tan on the fly to imitate connected bugs. 

Midges are the main insect to focus on in winter.  Our best producers have a little purple flash, but red and black are also important to have.  Most midges this time of year are size 20 or smaller, but sometimes a small tied 18 can work. Then make sure you have a light color olive/tan/white midge selection for the smallest of midges, talking sub 22 at that point.  Guide tip...a very small sow bug can be a great fly during a midge hatch!  (think grey/white size 22-24)

Another couple key flies up here almost year round are the wire worm, san juan worm and leeches.  Wire worms don’t have to use wire but it’s the shape of the hook, size 2-8.  We use some with wire, some with midge tubing, purple/red, red and red/pink.  Leeches are good to have as a point fly, they also reproduce in the wintertime....some larger and smaller patterns black and grey or combination. 

Eggs still might be a good attractor/point fly, I prefer bright orange this time of year.   Sometimes they are off eggs, but the introduction of the fall spawn rainbow keeps eggs in the river almost year round.  If you don't have or don't want to throw eggs a small orange scud works good too and kills two birds with one stone!

On scuds, again this is a year round thing in our rivers, a tan/grey/blue dubbing mix with flash and/or scud back does the trick. 

 Dry fly activity is pretty slow in January, there is often a short period where fish are hitting midge clusters, like Griffith’s gnat, midge emerges and the like, but probably not the focus.  

Lastly, having a small pseudo baetis, think size 22 RS-2 in grey is a good option in case the outside air temps get above freezing and there is a s cloud cover. 

A five weight is a good rod choice in the winter since we are generally throwing smaller flies and lighter tippet.  We have been seeing fish 20” and better fairly regularly so having a lighter feel fast action 6 weight is not a bad idea.  A 5 weight will generate be easier to cast and make better presentations. 

As far as tippet sizes and leaders go, the water is low again this winter and there's still plenty of moss in the river due to a warm end to fall and start to winter.  Now that temps have dropped down we should start to see the rest of the most reside until next summer. The smaller the tippet you use, the better the presentation and the more hook ups you'll have.  Issue is that with plenty of fish well into the 22-24" class and better if you're using 4x or below it can be tough to land the big ones especially with moss.  We like to use 0-2x for our top flies, 2-3x to our next fly and when using 3 flies go down to 3-4x.  If you understand your rod and reel well enough to play big fish on light tippets, there's no need to really go below 4x unless fishing to fish that are midging or hitting dry flies. From a boat you get a better drift and have more leverage so best to not drop below 4x, if you're wading and have good boots to help move around the river, 5x or below is an option. 

Hope you've enjoyed this report, we wish you the best heading into 2022 and would love to have you stay with us on your next trip!  We offer river shuttles, fishing friendly rooms and boat parking. Also if you want to treat yourself to a guided float down the river we offer float trips 365 days a year on the Big Horn and North Platte Rivers.  Of note for 2022 we now have permits to guide the Shoshone rivers, Bear River and Powder River, with more permits coming.  We hope to be your one stop shop for fly fishing in Wyoming!

Thermop Fly Shop

Two Rivers Inn

401 and 415 Park Street

Thermopolis, WY 82443


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