It's normal for your temp to vary a few tenths of a degrees within either phase. Some women see a lowering pattern in the few days approaching ovulation; some even see a distinct drop on the day of or before ovulation. As others have said though, the only thing that is "for sure" is three high temps in a row, which means you have ovulated on the day before the first high temp. Sites like fertility friend will draw what's called a coverline do that you can better see your own pattern.