Hi there

: Generally speaking you O the day before your temp rise... now sometimes women do get a dip down on the day they ovulate, but usually this coincides with the day before the temp rise. So, you could have temps that look like this:
cd 9 97.4
cd 10 97.3
cd 11 97.5
cd 12 97.2
cd 13 97.4
cd 14 97.0
cd 15 97.9
In this case there was a temp dip down on cd 14 and a temp rise on cd 15, so O was on cd 14.
HOWEVER! Some women (me included) don't get temp dips before O; only rises.
So for me a typical pattern could look like this:
cd 9 97.5
cd 10 97.4
cd 11 97.6
cd 12 97.1
cd 13 97.4
cd 14 97.5
cd 15 98.1
In this case, my temp on cd 14 was actually higher than my temp on cd 13 (and the only temp dip was on cd 12), but still not higher than my previous 6 temps because it was the same as my temp on cd 9 (i.e., 97.5). But I had a temp rise on cd 15 and so my O would be on cd 14, with a coverline of 97.6.
Hope that helps

!
++++++++++++++++good luck
Maura