ovulation question

Abigail
So is it the day that you have a temperature dip before 3 days of higher temperatures that you ovulate or is it the day after the dip? I'm feeling confused Glow has charted mine as the day after my dip but I think based on other symptoms I was feeling on the day of the dip and the day before that I could have ovulated on my dip day. Can anyone help me understand? 
Thanks