PCOS Ladies- When do you typically O?

I am on my 5th round of femara, my doctor is having a hard time getting my O day figured out, my cycles are never the same length. He thought I was O on day 15 however last cycle was day 19. I had an ultrasound on day 13 this month and I go in on day 17 for another one. So my answer to this is every women is going to very on when the O day is, try opk and best wishes...

I am in my 4th clomid cycle (this one being 150mg) I had a progesterone test on CD24 and it showed I had not ovulated. On cd26 I got a positive ovulation test. Waiting to hear back from the Dr. to see what to do next.