you need a thermometer that is specific for tracking your bbt. Usually you can find them at a drug store with the pregnancy tests or the "family planning" section. You want one that goes to two decimal places. So your readout will be 36.27 (I am using an example in Celsius as I am Canadian) and not 36.2
Make sure to take your temp at the same time every day. If you have to, set an alarm and then go back to sleep. Do not get up to pee first. just grab the thermometer and do it. Quickly write it down so you don't forget and then do your thing.
If you are off in your time, make a note why. (kids, job, emergency, travel). Make a note if your room is particularly hot or cold that night. do you sleep with your mouth open? That can affect it too. If you do, when you wake lay for a moment with your mouth closed and just breath evenly like sleep. Then take your temp.
if all else fails and you are still getting erratic temps you may want to take it vaginally. You need to find a thermometer that does that. Some BBT thermometers are oral only. Vaginal temps are warmer than normal so you can't do this mid cycle. You must wait and start a new one.
do you have PCOS? this can make your temps rather rocky but usually over time you will see a pattern for O.
If after all this you still see no spike for O it is likely you are not ovulating and may want to get checked out by the doc.
