I think you about nailed it here..."Drizzly, Olives, Windy, Water was up a bit, etc."...Perfect Baetis conditions, eh?! I remember a float trip with a guide friend on the South Branch of the Au Sable in MI in late May, years back, when it was so cold and over cast we almost called off the trip. At one point we took shelter under some sweepers when it hailed on us. The only thing on the water all day were these tiny little gray sailboats...Saved the day really.
We were out in it all day and stopped for some lunch...In the live well of the Au Sable riverboat I had a bag of ice (it never melted) and some beers. My friend looked at me shivering, as I was pulling a few out for us, and said, "Spence. Don't you have some hot chocolate in there?!"
My friend cursed the little buggers all the way down the river. I just thinned out the terminal end of my leader and tossed my plausible fake out there among the real ones as far out in front of the boat as I could. I actually caught my biggest Au Sable brook ever (until last year on the Mainstream) that day. I didn't have my microscope with me in the boat, but we took them for B cingulatus, so that was large brook trout on size #20/22 BWO dry fly...6x/7x tippet...No camera. I told Rusty at the Lodge this the next day and other than shaking his head about us venturing out on a day better spent in front of a fireplace he said, "No camera? I'd fire the guide!"
Give me a day, any time, where the weekend warriors stay home because of the weather and it's gray and the clouds seem only inches above your head. There was a decade or more there where most folks thought I was cursed. A huge cold front would settle in over Crawford county just as I was crossing the county line for a week of fishing. They started to joke that they wanted to know when I was going to be there and they would come the week after I left...I kept my little secret to myself...I would have the river pretty much to myself, the fish love Baetis, and I can't remeber much of a problem with the mosquitoes!
"Even when my best efforts fail it's a satisfying challenge, and that, after all, is the essence of fly fishing." -Chauncy Lively
"Envy not the man who lives beside the river, but the man the river flows through." Joseph T Heywood