Mine usually drops the day AF is due, sometimes the day before.
Thanks. I's nice to get a response.
What luvkayln wrote is correct or at least most common. Typically your temp should drop back to pre-ovualtion levels within 24-48 hours before your period however some women don't see the drop until after AF has started or sometimes even several days in. The delayed drop is much less common though. Good luck!
For years mine did the exact opposite of what is "text book". It would spike on cd1 and then drop later. I have been charting for 23 years. On average, mine tend to drop the day of af.
thanks. sorry it took so long for me to respond back. I didn't see it on the page.