Thanks all for the replies and thoughts! We unfortunately are not local so have to pick a date pretty far in advance and hope for a little luck. I’m leaning toward during the week immediately after Labor Day.
When are the bugs worst? Mid July to mid August?
General discussions on hiking in Oregon and the Pacific Northwest
The bug timing depends on snow melt. They are worst in the weeks after snow melts at that altitude. So in a given year the bug peak can be any time from mid-July to late August. I think it was early August this year.
Everything is a trade-off. There is no "best". September is probably the best if bugs and crowds are your main concerns but still want decent weather. The downside is most of the wildflowers are gone, the landscape is a bit dried-out looking, and you start flirting with possibility of rain or even snow.