Big Horn Valley's Autumn Chill - Nymphs, Dries, and Solunar Secrets for the Bighorn River

Big Horn Valley sunrise came at 7:17 AM with a chilly autumn bite in the air—locals found temps right around 41°F this morning, and we should top out near 62°F under mostly clear skies. We did see quick-moving clouds early, but the forecast calls for light winds under 10 mph, and the high pressure settling in promises steady conditions all day. Water temps in the Bighorn River have dropped into the seasonal low 50s, so things are shifting from summer hatches to prime autumn fishing. Sunset tonight is at 6:40 PM—if you want that twilight bite, be on the river by 5:30 and stay through dusk. No tides to speak of inland, but solunar activity lines up nice for anglers today—major activity windows run 9:30 to 11:30 AM and then again 9:50 to 11:50 PM, with minors right around sunrise and just before sunset. Fish seem to be taking the cooler change well, with browns and rainbows getting feisty, especially during those major windows. Reports from guides at the Bighorn Access ramps say the past couple of days saw steady catches on nymph rigs in the morning—standard fare like sowbugs, scuds, and small amber zebra midges producing best, especially drifted slowly through deeper slots. A 16–20 sized Pheasant Tail or a pink sowbug works great dropped under a split shot. Afternoon action has slowed at times, but those patient enough to twitch dead-drifted midges or baetis nymphs get rewarded as the sun climbs. Dry fly fans found luck late yesterday evening, when a surprise caddis pop moved fish into fast riffles near Three Mile Access just before sundown. A size 18–20 black caddis or a tan elk hair caddis got some solid takes, especially behind rock seams. A few good-sized browns topped the 19-inch mark, with strong numbers of rainbows from 12 to 18 inches—no monsters landed, but a steady bite and healthy fish by all accounts. Terrestrials like deer hair ants and foam beetles can still draw strikes, especially along grassy banks and overhanging brush in the midday lull. Local shop recommendations include the Cinnamon Foam Flying Ant and the Black Foam Beetle—the latter being hot upstream of the Bighorn bridge. For the streamer bite, smaller olive sculpins and classic black wooly buggers stripped slow get hit by hungry pre-spawn browns. Bait fishing has cooled but not stopped—nightcrawlers and salmon eggs worked in slower tailouts produced a few deeper rainbows for those tossing spin gear. Overall, fly anglers are finding more consistent success this week, but bait remains a solid option for new arrivals. Your best spots today: - **Three Mile Access**: Known for evening caddis surges and solid nymphing all day. - **Bighorn Bridge Riffle**: Productive for terrestrials and streamers, with deep slots holding the larger browns. - **Soap Creek Mouth**: Low pressure here, excellent for stealthy drifts with midges or swinging sculpins. Overall fish activity is steady for October, with the river moving into prime technical mode. Long leaders and delicate presenta This content was created in partnership and with the help of Artificial Intelligence AI.