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Does Daysy Count Temperature Readings if I Have Fever and I'm Sick?

The menstrual cycle can be different for every woman; every woman is unique. A cycle between 23 to 35 days is a regular cycle. However, the cycle can be different from month to month. Then it's great that everything is adequately monitored by Daysy so you know where you stand.

'Standard' pattern

It is very useful to have some examples from which to interpret the morning temperature or basal body temperature curve (BBT). Then you can also better understand your curve. The following picture shows what a 'standard' temperature curve can look like. Not every woman's curve goes like this; there may be a reason for this. You can read more about it in this blog and the extensive article on the Daysy site.

menstruatiecyclus verloop temperaturen vruchtbaarheid

During fever and illness

Fever is when your body temperature reaches at least 38°C. If this is the case, you are most likely sick and you will notice that your temperature curve is unusually high (see example curve below). The Daysyday app alerts you that your temperature is high and recommends measuring with a standard medical thermometer.

Temperatures above 37.8°C or below 35°C are automatically excluded from the algorithm and are not used for your fertility calculations.

koorts meting met Daysy cyclus tracker

What should I do if I am ill?

If you wake up in the morning and you feel different from normal, e.g. sick, hung over or overtired, skip the measurement that day and possibly the following days until you feel better again. Once you are better, you can continue taking readings. Daysy may then need a few days to give red or green again when she has enough readings again and thus knows where you are in your cycle.

What do my readings look like when I have a fever?

Suppose you continue measuring while you are ill. Look at the example above to see how Daysy observes but does not rate the 2 highest readings and picks up the colours again soon after.

Daysy does not calculate fever as ovulation and does not get confused! So you can just keep relying on Daysy.


Read the blog 'understanding basal body temperature' and see what your cycle might look like at:

  • Drop in temperature before ovulation

  • Temperature outliers

  • Illness and fever

  • Increased/decreased mean value



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