I suggest you take a class in a method and follow that method’s instrctions.
I use Creighton, so I don’t take temps and the Creighton instructions are solely on mucus.
You are fertile *whenever *you have mucus. Mucus helps sperm live and transport to the fallopian tubes.
Forget about averages of when ovulation occurs. It only matter when YOU ovulate. If you are starting to see CM around day 8 then you are fertile starting then. Charting will tell you how many days you typically have CM before ovulation. Sperm live between 4-6 days in CM (depends on the sperm!) Of course if you were trying to avoid, you would not have intercourse on those days. But, since you are TTC, then you could do so.
In the Creighton instruction you chart ovulation by your peak day of mucus. Peak can only be determined in retrospect, because it is within 24 hours of the last day of fertile mucus (same with STM, the thermal shift is what alerts you to ovulation, which you only can see in retrospect). When avoiding using Creighton you then count 3 dry days after peak and then you are infertile.
You aren’t going to be able to *predict *ovulation without an ovulation kit which tests hormone levels. So, you should be aiming for days when you have CM, and the clear, egg white CM that stretches 1+ inches is **peak **mucus. That would be a good time for intercourse if you are TTC.
The book Taking Charge of Your Fertility should help you immensely. Toni Weschler does a good job of explaining everything. She uses sympto-thermal charting.
The luteal phase is between ovulation and menstruation. It’s good to chart this too. A defective luteal phase (less than 12 days) is common in women with repeat miscarriages, and the doctor can help with that to make sure sufficient progesterone is present.
So, don’t count so much on averages and trying to hit THE ovulation day. Just work with your body when CM is present. Getting the TCOYF book will help you.