Reading Ovulation?

Kate • Baby #1 due June 2018 ❤️✨
New to the app! My ovulation week is this past Monday (6/19) to this coming Monday (6/26). The chart says my highest percentage of fertility (33%) is tomorrow, but it also says "Ovulation Day" is on Sunday 6/25. Im confused why high percentage isn't same day as labeled "Ovulation day". 🤔 Which day would be most important to have sex on? Thanks in advance for any help 😊