Your temp will generally stay high from the time of ovulation until you get AF (or if you're pregnant, it stays high). It will still vary a bit but the temperatures will for the most part all be higher than your temperatures before you ovulated (should all be above your coverline). I have read that it is fairly common for some women to have a drop in temp that goes below the coverline a couple days after ovulation which indicates an estrogen surge but it should go back up the next day. My temp would always drop the morning that I would get AF, so I would know it was coming. I believe they say more than 20 days of high temps is a good indication of pregnancy.