In the Natural Cycles app, you are able to log temperatures between 35.00-40.99 °C or 95-103.99 °F. If you try to log a temperature outside of this range (either lower or higher), you will see that certain numbers are grayed out and that you are not able to add the temperature.
If you happen to get a temperature outside of the temperature range that the app accepts, we recommend that you skip adding a temperature for that day and continue measuring again the next day.
If your measured temperature is below 35 °C or 95 °F, it is good to know that these low readings are often caused by how the temperature is measured. When measuring, please ensure that you place the thermometer as far back as possible underneath your tongue, right at the root of your tongue. What you are aiming for is the sublingual pocket located there (the thermometer should not be placed directly by your teeth).
Make sure that you only start the thermometer once it is in place and your mouth is closed, and that you keep your mouth closed during the whole time you are measuring.
To ensure that you are measuring correctly and that your thermometer is working as it should, we also encourage you to use the Measuring Training function in the app. You can find this by going to the menu in the top left corner > My Device > Measuring Training (please note that the Measuring Training is not available for NC° Thermometer Gen3 users).
With the Measuring Training, you can directly see if you need to adjust the way you measure, or if something may be wrong with your thermometer. If the app detects that something is wrong with either how you are measuring or the thermometer, it will guide you forward and you will be able to get a new thermometer if needed.
We write a bit more about the Measuring Training and its possible results here for the NC°Thermometer Gen1 and here for the NC°Thermometer Gen2. If you continue to get temperatures outside the accepted range, our Support team will be happy to help you troubleshoot. You can reach them directly via this link.