Depuy Spring Creek Throughout the Year

Tom Travis

Here’s a month-by-month breakdown of what the angler can expect while fishing DePuy Spring Creek, followed by discussions of specific hatches. Before continuing, I suggest you check the sidebar info about the creek, the trout, spawning on the creek, streamers, and a note about guides.

Seasons on the Spring Creek

The following information is based on normal conditions and covers an average day on the creek. This information is based on many years of fishing and guiding other anglers on this delightful stream. However, the information is in no way intended to be complete, as that would take an entire book or two. Nor are the methods or fly patterns listed the only ways to fish while on the creek. These are just suggestions for anglers who have limited spring creek experience and do not wish to use a guide. There are no hard and fast rules about what will or won’t work on the creek, and I strongly urge anglers to try new flies and methods and otherwise be creative while spending your day on the creek. The information listed has worked well for myself and folks that I guide, and I hope that it will help you get started on the creek, or help you better understand the challenges of fishing this creek. Each month offers some differences. The best advice the spring creek angler can receive is to pay attention and be observant!

The water temperature of DePuy’s normally is around 52 degrees. On the hottest days of the summer the water temperature on the lower end of the creek may reach 62 degrees. One of the coldest days ever recorded was -39 degrees, and the water on the upper end of the creek was 50 degrees and the water on the lower end dropped to 42 degrees.


During the month of January you will find the weather to be the only limiting factor. Because this is a spring fed fishery the water temperatures are always fairly constant. During early January the angler may still find some spawning brown trout, and during late January the angler can begin to encounter some early rainbows beginning to spawn. The hatches and surface action found during January are directly related to the weather. During a cold winter there will be a few days of sporadic midge activity. During a mild winter the midge hatches may be found on a daily basis, along with a scattering of Baetis. Remember, during the winter months the water level is at it’s lowest as the weed beds die off. Therefore the creek is low and the trout will be a little more spooky and shy. This is certainly true on bright, sunny days. The angler needs to be a little more cautious in approach and presentation. If you have fished the creek during the summer or fall you may find that your favorite area doesn’t hold the number of trout that it did during those other seasons. If this is your problem, remember to check out other sections of the creek. Understand that the trout haven’t left the creek; they have just moved to a location which offers a better food supply and shelter.

Pumping stomachs in January has shown that 95% of the time aquatic food forms make up 96% of the trout’s diet. This makes nymphing the most effective method for fishing the creek in January.


Here in Montana, the month of February can be a paradox, with air temperatures in the high 40’s to below zero. During February the rainbow trout spawning will slowly build. The midge hatches generally increase during the month. The Baetis hatches will continue to be scattered and sporadic. Regardless of how harsh the winter may be, it is a rare February when the angler can’t spend at least half the month fishing. For those of us who need a fish fix, February can be a Godsend!! I have a few clients who come out to ski at Bridger Bowl during January or February and if the weather permits, will spend a fun day on the creek. If you have never fished the creek during the winter you should give it a try.


The month of March is normally the last harsh month of winter. The angler fishing on the creek should be prepared and dress in layers. However, there is some great fishing in March. During the month you see the rainbow spawning run from the Yellowstone River reach its peak. There will also be good midge hatches along with the baetis hatches. As the month draws to a close the baetis hatch will increase. March starts the time period when the nymphing is excellent; however there are plenty of opportunities for those who prefer hatch fishing. Out of 31 days in the month, you’ll be able to fish approximately 26 days.


April is the month of change on the creek. Winter is about over, the days are getting longer and the weed beds are starting to grow. In early April the water levels are generally at their lowest. As the weeds grow they displace the water, causing the water level to rise. From the first of the month until around mid-month there will still be a fair number of rainbows spawning. The midge hatches will continue and the baetis hatch will hit its peak. Along about mid-month the caddis hatch will start to appear and this hatch will become stronger as the month progresses. In April, terrestrials once again start to appear in the form of ants. So, as you can see, April brings the angler many changes and challenges. The angler needs to be very observant and have a well-stocked fly box to take full advantage of the many angling opportunities offered.

NOTES ON APRIL WEATHER: Yes, winter is definitely on its way out. But we can still get a late snowstorm. Therefore, you should come prepared with good, warm clothing along with good rain gear. Dress in layers. Remember, you can always shed a layer or two. Some years April is a very warm month with temperatures from 50 to 70. Other years the temperatures may be from 25 to 45, so be prepared.


May is the month that means winter has finally gone and the days are getting longer and warmer. May can also produce rain showers, so don’t leave the rain gear at home. During early May the angler will encounter heavy caddis hatches, which will taper off as the month progresses. The angler will also encounter fair to good midge hatches. During the month the angler may also encounter some scattered baetis hatches, though they can’t be counted on. From about mid-May on, there will be some scattered callibaetis hatches. On some days the hatching activity may be scattered, and on the brighter days the trout will be a little more wary. Also, the beetles will start appearing this month. Because of the conditions and the many changes that take place during the month, the greatest asset the angler has is the power of OBSERVATION. The best advice I can offer is be willing to move around and try different methods and patterns. Those who get “stuck in a rut” are often frustrated by the end of the day. There is plenty of nymph and dry fly action for the angler to choose from.


Everything that happens in June depends on the weather patterns of the previous months. A long, cold April and May will mean that the weed growth has been retarded. The angler may find the creek water levels lower than normal and the trout somewhat shy and spooky. If this happens, the angler will find a few midge hatches, scattered callibaetis and even a few tail-end baetis hatches. Often the angler will find the best dry fly fishing to be with midges, ants and beetles along with attractor dry flies. If the previous months of April and May have been warmer than normal, the angler will find the creek level a little higher than normal, along with expanded weed growth and then there will be early hatches of Pale Morning Dun mayflies. Now, if the months of April and May are a normal mixture of warm periods and cool periods, the angler will find more normal conditions. This means that early in June the angler will find some midge activity but any other hatches may be limited and scattered. It also means that attractor dry flies and nymphal imitations may be the most effective. As the month of June progresses, the Pale Morning Duns will begin to hatch and are generally in full swing by the 20th. There is also some limited caddis action to be found during the month. From about mid-June on, the cutthroat trout begin spawning. During this time period rainbows love to lay below the cutthroat redds and feed on eggs. June is also the spawning time for the Mountain Suckers and the rainbows will follow these schools of fish around to feed on the eggs. June can be a confusing and challenging month for the angler who is unfamiliar with the moods of the creek. However, once a little knowledge and experience is gained, the angler will find June a great month to fish the creek.


July brings, with full force, the hatches of summer. The fly fisher who visits the creek in July will encounter many different and challenging opportunities. The day will start with the trout feeding on leftover spinners from the night before, or they may be midging. If the weather has been unseasonably hot, day after day, the angler who arrives early on the creek in the morning, say around 7AM, may find a PMD spinner fall. The morning hatch is the PMD (Pale Morning Duns) and in the mid-afternoon some sections of the creek have some excellent caddis emergences. The late afternoon to early evening is the time period for the Sulfur mayflies. The PMD spinner fall will occur during the late evening, as long as the wind is not too heavy. During the evening there may also be some scattered caddis dry fly action. Throughout the day terrestrials, such as ants, beetles and crickets will produce some nice trout. By late July hoppers begin to appear on the creek. The spawning activity of both the cutthroat trout and the mountain sucker continue during July but are pretty much finished by mid-month. By the 20th of July the weed beds are fully recovered and the water levels may rise 12 to 16 inches from the winter lows.


During the month of August you will see the continuation of the PMD hatch, though this hatch will fade as the month progresses. The sulfur and caddis hatches will continue and you will see the Trico hatch on certain sections of the creek. During the evenings there will be both caddis and midge action along with a scattering of spinners. August is an excellent time for terrestrials. Hoppers, crickets, ants and beetles all produce nice trout. The weed beds on the creek will impact the fishing on the creek in some sections, bringing many new and challenging presentation problems for the angler to solve.


September is a month that can bring lots of change to the creek. The angler may encounter late hatches of PMD’s, tricos, sulfurs, and Pseudocloeons. During early September the sulfur hatch will fade pretty fast, as will the tricos and pseudos. However the caddis can sometimes last until late in the month. The main hatch during the month, or maybe I should say the most dependable hatch, are the midges. From mid-September on, you might see a few early baetis hatches and terrestrials such as hoppers; crickets and ants are still very effective. During the first ten days of the month be on the lookout for flying ants, both red and black during the late afternoons and evenings. The weather in September is generally nice with daytime temperatures in the 70’s and there may be a few days in the low 80’s. But on occasion an early storm will drop down out of Canada and the temperatures can dip down to the 40’s with snow in the mountains and rain in the valley. September is truly a transition month were every day on the creek can be different, challenging, and exciting. To meet these conditions the angler must be well prepared.


October weather can be a really mixed bag, from clear, bright, calm days to cloudy, rainy and windy days, or possibly even an early snow shower or two. Clothing-wise, come prepared and dress in layers. It’s easy enough to shed a couple of layers but it is real tough to put on additional layers if they are at home in the closet. Having said that, I will tell you that October weather is generally pretty good, with daytime temperatures ranging from 55 to 70. Another little secret I would like to share with you is that October is the most UNDER UTILIZED month on the creek. The fishing can be super. In early October there are still a few terrestrials around and ant and cricket imitations can be very effective. The two main hatches for the month are midges and baetis and these hatches are pretty reliable on a daily basis. In late October the angler will start to see spawning brown trout on the creek, and a well placed streamer or a dead-drift nymph might mean the biggest fish of the trip. The weed beds are still in good shape during the month, though they are starting to die off for the season.


November means that summer is over and winter is fast approaching. The first half of the month is generally pretty good, but the weather will dictate how much fishing there is on the creek. November tends to be a windy month. However, there are still baetis and midge hatches, along with spawning brown trout. The spring creek trout tend to move around and shift their locations depending on the time of year and the major food forms available. Therefore, if you have fished the creek in the summer and once again return to your favorite spot in November, you may find it to holds fewer or smaller trout than in the summer months. This means that you, the angler, must use your powers of observation and seek out the trout. The weed beds are dying off, the water levels are dropping and the trout are shifting their positions. Besides the action from the hatches, nymphing and streamer methods are very effective during this month.


The spring creek fishing in December is directly related to the weather. There are some days when the fishing is good and the angler will encounter some baetis action, though the main hatch during the month is midges. During December much of the best action will be with nymphs and/or streamers.