Flip the switch: High-country cutts on and off

It never ceases to amaze me how fishing can change drastically from one day to the next.
Take last week, for example. I hiked into a mountain lake that contains Bear River cutthroat trout. This lake gets hit hard by Nebraskans and other meat fishermen, so I wasn't expecting much. If I caught five or six fish, I would have been happy.
I packed in some neoprene waders for the cold water and waded out toward a dropoff where cutts have cruised in the past.

They were there again. My first four casts with an emerger produced four hits, of which I landed two cutts. The rest of the day was pretty steady action, especially after I switched to an ant pattern. I caught and released 24 trout and missed at least that many strikes. The cutts in this lake have an uncanny ability to sense when I'm gazing at the scenery or looking for my dog. They always choose that moment to strike.
I made plans to return two days later with a fresh supply of emergers and ants. Again, I packed in waders and waded out to the ledge. Again, my first three casts produced hits although I didn't land any of them.
Then it slowed down. I mean, really slowed down. After three hours of casting, using the same patterns as two days before, I quit with a grand total of five trout landed and released.
Both days were about the same temperature. The wind blew out of the east each day, about the same speed.
The one variable seemed to be cloud cover. My first, successful day, there was sunshine all day. But two days later, it was overcast with only a few breaks in the clouds.
Of course, there could have been some other factor that I'm not aware of that made Day 2 so much less productive than Day 1.
But any time you can spend a day in the mountains, catching even a few beautiful cutthroat trout, is a day worth living.