[Skip to Content]
Time is Money. Find out more about how this app can revolutionize the way you weight your truck.

Spring Fly Fishing HOTTEST Hatches

By on March 1, 2019

Roadking Outdoors Contributor

Fly fishers around the country wait long, cold months for March to arrive. It marks the time of slow and steady temperature increases, awaiting the higher sun and sprouting of spring. With these subtle changes in temperatures, along with the longer days ahead, the fish start switching into feeding mode. Of course, the fish feed all winter long on tiny midges in the freezing waters, but in spring the bug life is much more plentiful. March and April mark the times for one of my favorite bug hatches: the Blue-Winged Olive (BWO). Personally, I’ve seen BWO hatches as early as late February but that only happens on rare occasions, following warm winters. 

When & Where 

During a typical year, the weather across the country starts to warm around mid-March. This new taste of warmth sparks the BWO hatch, and it is something you want to make sure not to miss. Blue-Winged Olives belong to the mayfly family and they thrive around North American trout streams. BWOs are small in size, and because of this they typically have up to three hatches per year. They often hatch in impressive numbers and live in the water long before taking flight. The fact that their hatches are so large makes them a staple “favorite hatch” for fly fishers everywhere. 

Flies to Buy

Typical sizes of dry fly range from 16 to 22. At most fly shops, the fly pattern goes by “BWO” or Baetis. Blue-Winged Olive flies can be used in forms of nymphs, emerges and dries. Check with your local fly shop to see what is hatching in terms of form and size. When heading to the river or stream, look for flies along the top of the water. If BWOs are taking flight you will see abnormal amounts of tiny grayish-olive flies flying slowly close to the top of the water. If they are hatching, it is common to see tons of trout feeding on the surface. 


For the famous BWO dry fly hatches, bring a 3-to-6 weight rod to the river depending on the size of the trout in that water body. For tippet and leader, stay around 5x to 7x. Because BWO flies are typically very tiny and thin, a strong leader is a must. I like to use fluorocarbon 6x when fishing BWOs in March and April because it’s strong, hard for the fish to see and thin enough to tie on size 22 dry flies. If you are out fishing mid-March or April and you do not see any dry flies out, the BWOs are likely in their dun form below the surface. Fish their nymph or emerging patterns below surface.

Depending on the river depth, put the wet fly patterns a foot or more below a small indicator. When that indicator moves, goes under water, or even experiences the slightest twitch, set your hook! That’s a feisty trout going for your tasty fly. Fight the fish, and land it in a net. Once you’ve caught your first trout on a BWO dry pattern during a hatch so thick you can’t keep the harmless bugs off your face, you’ll also be hooked! Trust me. 

Best Times for Trout

Like almost all times of year, dawn and dusk are the best times to fish for trout during spring. That being said, I’ve been on the river and experienced immense BWO hatches at 2:00 in the afternoon! No time is a bad time to fish during BWO days since the hatches are plentiful and the fish are hungry after a long, cold winter. BWOs are mostly found on rivers and creeks but their patterns can be used on lakes as well. Hatches start typically around March, and depending on the year, can last all the way until early fall. 

No hatches are as large as the ones in March and April, however. Get out on the water with a good selection of Blue-Winged Olive patterns, and enjoy the beauty of fishing and the great outdoors. All photos used to illustrate this article are trout that I caught on a BWO pattern. Thanks for reading, and tight lines! 

About Warren Eulgen

Leave a Reply

Your email address will not be published. Required fields are marked *