A basal thermometer is a digital thermometer showing two decimals, (for example 36.29°C). It is more sensitive than a regular thermometer. This is very important when measuring your basal body temperature, which rises by 0.2-0.45°C after ovulation.
This is why you need to use a basal thermometer with Natural Cycles, and not use a regular thermometer. A fever thermometer measures only to 1 decimal and not 2 as the basal thermometer does.
It will take a few weeks of measuring for Natural Cycles to understand and get to know your unique cycle. If you just got started, keep measuring and adding data so Natural Cycles can find ovulation.
Good to know: when you sign up for a Yearly Subscription at Natural Cycles, you get a basal thermometer for free as a welcome gift from us!