It is alright if you miss a day or two of measuring but you should measure as often as possible, especially if you just got started with Natural Cycles, to get the best results. The more data you enter in the app, the better will the algorithm gets to know you and your unique cycles.
With less data, the app may give more red days as a safety precaution, but this will even out again once you start adding data regularly again.
Always add your temperature as deviating if:
- You’re sick, regardless of if you have a fever or not
- You've had more than 2 glasses of an alcoholic beverage for dinner, or alcoholic drinks later during the evening
- You wake up more than 2 hours later/earlier than usual (long sleep-ins, very early rise)
- You measured after getting out of bed, or have been awake for a while, as this reading will not be your resting temperature (BBT).