You can start now. Just take your temperature first thing in the morning, before you get up at all (I keep my thermometer on my night stand, so I just roll over and grab it). Once you get up, your temp jumps and makes it invalid, so you have
to do it before you get up. At the same time every day is best and will give you the most accurate results. Then keep a record somewhere (FertilityFriend.com
is a good site for info and recording). What you're looking for is a sustained
temperature shift up by about 0.5º; it's completely normal to have an odd high or low temperature, but it doesn't mean anything unless it stays that way. Unfortunately, charting BBT isn't a good way to know when you're going
to ovulate (though some women notice a dip in temps the day of), but it's the only way to know for sure
when you have ovulated.
at 9:07 PM on Aug. 31, 2010