I've been reading that the blacktail deer rut will begin within 5 days of the 2nd full moon following the Autumnal equinox. Sounds pretty involved. I've also heard that the very first cold snap will trigger it. According to my calculations the rut in Washington for blacktails should begin around the end of October or beginning of November. Is that what everyone else has experienced? Also, if a doe in estrus hasn't been bred within 24 hours and she falls out of estrus. She will again be ready to breed 28 days later. Has anyone had good success with this secondary breeding time? Are many of the bucks still primed and rutting? This seems like it might occur right around Thanksgiving. Any input. I would like to arrow a nice buck.

I don't know the official start date,but I've always heard it starts around the time the late rifle hunt starts. The late hunt is usually around the 3rd weekend of November.

I've found the same thing. Starts in late oct. and peaks around the 10th of Nov. I've seen some really nice bucks still running does well after late buck. I think for your best chance to arrow a nice buck in the rut you need to go east. Up in the Republic/Curlew area.

I've read that the reduction of light hitting a deer's retina is what triggers the rut. Day length and cloud cover would then be the cause of rutting. I probably read it on a hunting bulletin board, but someone I have hunted with got the same story from a game warden.
Most of the rut activity I've seen has been in the late season but some has been in late October. These two pictures are of the same blacktail killed last year on October 26th. Judging by the neck I'd say he was into rut.