Runoff Update and Season Fishing Forecast for June 1, 2024

Posted on June 1st, 2024 in Season Forecasts, Weather & Water Conditions

If you’ve been following our season fishing forecasts, you know that we saw a warm, dry winter here in Yellowstone Country. For much of the winter and spring, we’ve been anticipating dreadfully low water and tough conditions in late summer. Thankfully, May has largely been cool and very wet, so it seems likely we’ll avoid the worst impacts of the warm and dry winter.

This isn’t to say it’s all wine and roses. While remaining snowpack is above 90% of normal for the date in all of our key basins, and water year precipitation is close to normal, our peak snowpack was only 70% of normal or thereabouts as of May 1 and we remain locked in moderate drought. Long-range outlooks through early fall suggest hot/dry weather which will make these deficiencies worse. So we are still going to have low water for most of the season, and if the hot/dry forecast comes true this water will be very warm in late July and August. 2:00 closures are likely in many areas. This is still an improvement over previous outlooks, when we saw strong possibilities of complete fishing closures in many areas.

Overall, we now expect conditions similar to 2012, 2013, 2015, or 2016, rather than the extreme drought and record-low flows of 2007 and 2021. We’d much rather have the near-normal or above-normal flows of 2009, 2010, 2014, 2017–2020, or 2023, but we’ll take “not what we want but not catastrophic” over “the creeks are running dry and everything is on fire. Run for the hills!”

General Summer and Fall Fishing Outlook

We are now edging into peak season. All rivers with the exception of the Lower Madison are in some stage of runoff. Those that see heavy runoff (the Yellowstone System in particular) are chocolate brown and blown out, and will be for a while. Those that see light runoff, such as the Upper Madison and its sources the Firehole and Gibbon, are tea-colored but fishing well.

Runoff will begin receding somewhat early this year, probably between June 15 and June 20 in our core operations area. The most consistent fishing will occur during the month of July. By July 20 we may need to quit fishing between 2:00 and 3:00 if the weather is hot and dry, but if we have some cooler, wetter weather breaks, fishing may remain good all day in July.

By August, low, warm flows will dominate and it seems unlikely fishing will be worthwhile most places after 3:00PM. Shady mountain creeks are the only likely exceptions except on the coolest days. 2:00 closures range from possible to almost certain depending on the fishery. The Lower Madison River, Gallatin River downstream of Gallatin Gateway (and the entire East Gallatin), and other low-elevation waters are the most likely to see 2:00 closures. Full closures are possible on these waters as well. 2:00 closures have a 50/50 chance on the Yellowstone east of Livingston and a bit lower than that south (upstream) of Livingston, where the water is colder.

August fishing quality will otherwise depend on cloud cover. Clouds will equal better fishing, particularly on the surface. As for dry fly fishing, late summer and early fall (through mid-September) are much more likely to be “ant season” rather than “hopper season” most places. Basically, the lower and clearer the water, the less eager the trout will be to take a chance on big grasshoppers. Rough water sections of the Yellowstone and its tributaries in YNP are the main exceptions that might still see the fish chasing big mouthfuls.

September will see cooler water and better fishing after lunch than before except on the hottest, brightest days, but the fishing quality will still depend on clouds. Cloudy weather will offer much better dry fly fishing, which will slant towards mayfly-style attractors after Labor Day and especially after the 20th or whenever the first fall rains hit.

Detailed Predictions for Specific Watersheds

The following predictions cover the anticipated duration and magnitude of the spring melt as well as when we anticipate the most consistent fishing of the year to occur. Fisheries are discussed first via jurisdiction (Montana vs YNP), then according to their expected end to the spring melt.

Montana Fisheries

Paradise Valley Spring Creeks: No runoff and no drought impacts, though right now fishing is tough because we’re between hatch cycles. The next great window is from roughly June 20 through July. This period is almost always booked completely solid due to dependable PMD hatches, and this year is no exception. Late cancellations or possibly booking a guided trip with one of the “corporate” outfitters that block-books access, such as Montana Angler, are your only hope for access during this period for 2024. Even many days in 2025 are already booked up.

Lower Madison River: While flows are rising, they’re still quite low, at around 2500–2800cfs. Cloudy days are likely to offer the best fishing moving forward. Dry-dropper can work if you’re seeing some fish rise. Look for PMD and Yellow Sallies now, with tan and White Miller Caddis soon. Crayfish and a mayfly nymph dropper is the best combo if there’s no hatch. By June 25 or so this water will be too warm to fish ethically after 2:00PM, and 2:00 or full closures are likely after July 4.

Upper Madison River: Somewhat dirty with spring melt, but still fishable subsurface and likely to stay that way. Look for Salmonflies and clearer water after June 20. The best fishing will occur between June 15 and July 15, with spookier fish interested in smaller flies thereafter. This water will get low but should not see any mandatory 2:00 closures and probably not even any water exceeding 70 degrees except near Ennis, and only then on the hottest afternoons.

Gallatin and East Gallatin Rivers: Both are near peak runoff right now. The East should come in around June 15. The mainstem a few days later. The best fishing on the East will definitely take place prior to July 20 and 2:00 closures are almost certain thereafter, with full closures possible. The same goes for the lower mainstem downstream of Gallatin Gateway. The mainstem from the YNP boundary to Gateway should fish okay into August if it’s not too crowded, and is unlikely to see any closures.

Jefferson River: Has been in and out of runoff for the past month. This will recede around June 15 and there might be a week of fishing before it starts getting too warm after 2:00. Mandatory closures are likely in July and August, with 2:00 closures basically certain and full closures likely. This river leads a hard life due to its low elevation and drastic irrigation demands both on it and on its sources, the Big Hole, Beaverhead, and Ruby.

Boulder River: Has been in and out of runoff lately but is shot now and likely to stay that way. The level is still fishable—quite good, actually—but it’s near max runoff and so will be as dirty and full of junk as it ever gets. Peak runoff will likely occur next week, and the river should become truly fishable for tough anglers (and oarsmen) by June 15. The best float-fishing will occur from June 20–25 for about two weeks. The lower river should remain floatable until roughly July 15, depending on rainfall and heat. The upper river will be best from July 4 through early August (for wade-fishing only) and won’t get too warm to fish ethically, though the fish might get spooky.

Yellowstone River: We have been in and out of runoff since late April, with the last window of clear water concluding Monday. We are now forecast to hit maximum flow early next week. While it’s possible the Yellowstone will begin clearing up around June 15, June 20 or so seems more likely. The Salmonfly hatch will begin shortly thereafter. The best fishing will occur in July. It’s possible that the last week of July will get shaky on some stretches if we have exception heat by mid-July. August and early September are huge question marks right now. Basically if we have a cooler, wetter summer than is forecast, the fishing will be okay and closures will be limited or nonexistent in August. If we have a hot, dry summer, 2:00 closures seem likely from Gardiner to Laurel and full closures are conceivable east of Livingston. River-wide full closures are extremely unlikely thanks to the cool spring. We will need finer tippets and smaller flies in August and early September than we’ve needed in 2022 and 2023.

Stillwater River: Muddy now, or at least too high. Stretches from Nye to Absarokee will come into play between June 15 and June 20 and be the best option until mid-July. Mid-July through the end of the month will see the entire river a good float bet. August will see the upper river too low for floating but good for wading, while the lower river is excellent for floating. Late afternoon fishing will be poor except on cool days for most of August (and probably even the last week of July), but 2:00 closures seem unlikely and full closures won’t happen unless there’s a big fire or something. It seems likely the lower Stillwater will remain high enough to float through August, but will probably get too low by Labor Day, unfortunately. Lots of late summer and fall rain are the only way this water will remain above 425cfs, which is our cutoff for floating even with adventurous clients.

Creeks: Meadow streams like the upper Musselshell will be best from June 5 through June and be too warm thereafter. Full closures are likely from the headwaters to Harlowton (the trout water) in late July and August, or at least they should be implemented. This river is sparsely fished, so FWP might not bother. Mountain creeks will be best from July 10 through mid-August and will be trickles by late August. While 2:00 closures are unlikely, the fishing will not be as good as usual due to the low flows.

Yellowstone Park Fisheries

It now seems unlikely the park-wide 2:00 closures on flowing water will occur as they did in 2021. That said, many waters will be too warm to fish ethically for much of the summer and may/should see closures, and even some of those waters that remain cool enough to fish will see tough conditions in August and early September.

Lakes in YNP: All are now ice-free and accessible, though the trails in will be swampy, wet messes until June 10 or so. The best fishing on all will begin any day now and continue through June 25, then gradually tail off through July. August and September are generally tougher on lakes and might be tougher yet this year due to expected high weed growth.

Firehole, Gibbon, and Upper Madison Rivers: All are clear, below normal in terms of flow, and fishing fair to great depending on the day. On the Firehole, the best fishing will occur prior to June 15 and after September 15. 70+ degree water may occur in late afternoon starting as early as next week downstream of the Lower Geyser Basin, and the entire river may be too warm for ethical fishing in the afternoons after June 15 and overall after June 20. The Gibbon will be best prior to June 15 downstream of Norris, but should be okay there until June 25 except maybe on the hottest, brightest afternoons. Ethical fishing will conclude for the summer by July 4 even in the mornings. We don’t fish the Gibbon again until October due to slower early fall fishing compared to many other options, though temps will be fine by Labor Day. The Madison will be best between now and June 20, too warm by July 4, and good again by Labor Day.

Yellowstone River (Grand Canyon): As is typical for the Yellowstone in the Grand Canyon during drought years, it is fishable on a day-to-day basis depending on if the river is coming up or dropping. Nymphing with stonefly and large attractor nymphs (#12 Prince behind a #6 Minch Stone for example) or streamers such as Woolly Buggers are the tickets as long as the water is more green than brown and there’s at least a foot of visibility. The real deal will begin here roughly June 15 as the creeks drop out of runoff and turn clear and the river stops rising and scouring the canyon walls. This water should remain cooler than any other stretch of large river in the region, and because it’s narrow and deep the fish will be somewhat less spooky. That said, the easy-access areas such as Tower Falls will get hammered, so you’ll have to beat yourself up to get on unpressured trout.

Gardner River: The Gardner will be in and out of fishable clarity downstream of Boiling River through the 15th. If it’s green, fish stonefly and large attractor nymphs. The middle Gardner (Osprey Falls to Boiling River) and headwaters will be too cold even if they are clear. The headwaters were filthy on Wednesday. After June 15, look for Salmonflies on the lower. The middle river will become fishable at about this time. The upper will be about June 25 simply due to flow rate. The best fishing on the lower Gardner will trail off by July 15 and the water will be too warm to fish ethically until Labor Day, but not any good until after September 20 due to weeds. The middle will fish best in July and early August and get gradually tougher after that before getting too cold more often than not in early October. The upper river will fish best in July and trail off badly in early August as the river gets skinny. We are turning down “beginner brookie” trips here in August now out of an expectation of awful fishing within a 30-minute hike to the road, due to a combination of heavy pressure and skinny flows.

Yellowstone River (Elsewhere): Muddy. With the hot forecast, the river won’t come into shape here before the 15th, and it will really be about the 20th. The best fishing will occur in July and maybe the latter three weeks of September. August and early September will be weather-dependent. 2:00 closures are fairly likely in early August, though if we luck into a cool July they might be avoided.

Lamar River System: Muddy. The canyon portions of the Lamar and maybe Slough Creek will come into play between June 20 and the end of the month, with the precise date depending on the progress of the melt. Otherwise, July 1 is the likely date for everything else. The best fishing will occur in July. Closures are possible but somewhat unlikely in early August. That said, by August 10 these streams will be trickles, and the fish will be scarred and have more piercings from busted-off hooks than your average 20 year-old at a goth music show. Soda Butte in particular will be an eastern-style combat fishery in August and September, and it will often be difficult to impossible to find as much as 50 yards to yourself. Why come to Yellowstone to fish in a crowd??? We haven’t fished here for fun in over 15 years due to the crowds, and it has been five or six years since we’ve even guided on it.

Creeks: Some of the headwaters on the park’s central plateau should be ready by June 10, most of the rest by June 20. The steeper mountain streams will have to wait until around July 1. The best fishing on the meadow-type creeks will occur from June 20 through July 20. The best fishing on the mountain creeks will occur from mid-July through mid-August.