I was having a discussion with a breeder about double clutching and off season breeding a few months ago and why the percentage of success is low. We both had the same thing in mind at the onset of the conversation. Snakes can sense the seasons. More precisely they can sense the long term barometric pressure changes. We also thought that chances of off season breeding and double clutching would have more success in 3 season states.
Breeding with my corns is tied into change of the seasons more than temperature of brumation. Do to a move last year I had no choice but to brumate at 68 degrees and all the corns that bred in prior years did so this spring. My other species on the other hand did not except for a pair of beauty snakes which will mate anytime I pair them up.
Since your in Cal. keep trying once a week. No harm will come in continuing to try. I will be interested to see if your successful in relationship to our thoughts on off season breeding. Good luck