The "magic" in my story that allows for werewolves (and vampires etc) to exist isn't necessarily based on any physical phenomenon related to percentage of moonlight or anything like that. Actually, my vampire hunter - Steve Van Helsing - explains it better than I can:
“One question,” said Angela. “In your experience as a vampire hunter…which religious artifacts work against them? I mean, I guess I’m trying to ask, like…”
“Which religion is true? All of them, really. In a way. Sort of. A vamp will recoil at a Buddha as quickly as it’ll recoil at a cross. It’s not the literal power of God or whatever that hurts them. I’m not actually sure what it is, but I have my theories. I think it’s more of a humanist idea –the fact that humans, mere mortals, can collectively create an idea as powerful as a religion, can collectively believe something so massive without any evidence, and pour that collective energy into it, into the hope of something bigger than themselves, somehow that positive, collective energy can damage a vampire. It’s not that religions are true, per se. It’s the focused energy of the human, of the mortal, to try to find meaning in the meaninglessness of existence – somehow, that energy is poison to a vampire.”
“But there has to be something beyond science, or vampires and werewolves wouldn’t be possible, right?” said Angela.
“Possibly. But what was it someone said once? Any sufficiently advanced science would be indistinguishable from magic? We just don’t have an answer for how werewolves and vampires work right now. But maybe one day science will figure them out too.”
“An atheist vampire hunter. Never thought I’d see the day,” said Angela.
“Not an atheist,” said Steve. “A humanist. An optimist, really. I believe in people. And that’s why I want to protect them against monsters.”