HOW TO KNOW WHEN TO USE CHIRONOMIDS?????

I remember a trip to Blue lake in the Sinlahekin that may answer the question.
I was fishing the little lake at the South end. It was early July and many adult Damsels
were breeding over the shallow weedbeds. The females were dipping down to lay eggs
and the monster trout were cruising underneath. I think every fish in the lake was in the shallows.
I tied on an Adult damsel and began casting. My imitation was so damn good that I noted
on several occasions Male Damsels would lite on it and try to breed. No Joke!!!!
After an hour or so of fruitless casting I noted the trout were not interested in Damsels
unless they were hovering an inch or so off the water. It seemed to be some sort of game, even spent Damsels were ignored.

WHAT TO DO? Being a chironomid fool I decided to try one. I put on a black/white everglo rib #16
and hung it under a yarn indicator and cast to the area fish were cruising. I noted if I cast near
a fish it would spook. But I just let the chronie sit suspended there about 18" under the
indicator. Soon they would come back. The rest of the day was about a 25 fish day.....all
on chironomids.

Moral of the story: Anytime is the time to try chironomids.