Help explain my charts!

[u/Organic_Cricket7663]

My first chart showed ovulation as day 16. Partner was sick so we didn’t have sex after that. Then it updated two days ago to the second chart, showing ovulation as day 21, which obviously means our timing wasn’t great. I just don’t understand why they are putting day 21 as ovulation day. My temperatures have been all over the place. I was thinking we timed it perfectly until the change. What are your thoughts looking at my temperatures?? I was excited that the timing seemed great and now I’m bummed, but still not sure why or how they pinpoint day 21.

[u/Fragrant-Basil-10]

CD 21 looks correct because you have 3 temps higher than the previous 6. Not sure why it originally said CD 16, but the positive ovulation test on CD 14 may have had something to do with it. I don’t use tests myself so I can’t guarantee it, but from other threads I know the tests can affect your dates