Somewhere between 55-65 degrees. Humidity depends on what I want to do, and which end of that temp scale it is at. 55 degrees and a bit (not a lot) humid is invigorating - just about perfect for dog walking or hiking!
But when it comes to the daylilies, sigh... they want it warmer. A daytime temp of 55-65 could mean nighttime temps as low as 46-52 degrees, which means poorly colored blooms, blooms that won't open, and less than optimal plant growth.
You can't have it all!