In order for temping to be accurate we have to: *Temp at the same time everyday (I have an alarm) *Don't drink ( can spike your temp) *Get at least 3 hours of solid sleep before you temp (good luck if you pee through the night ) *sleep in the same conditions and temperature every night ( ya right! This one never really works well for me) *don't get sick (I have gotten sick twice and I noticed slight fevers that I would not have normally even checked for) As you can see there can be stupid little things that can make it hard to follow. I use mine as a tool along with OPK and CM tracking, but is by no means the only thing to tell you if you ovulate.