Tips on Taking Your Basal Body Temperature


Getting started taking your temperature every day can seem daunting at first. I created a free guide to help you out, available right here.

I’ve also listed a few hints below that may help as you’re getting started on your cycle charting journey.

The big picture is this: you’re looking for an overall pattern

  • Slight fluctuations day to day are not cause for concern (repeat: do not freak out if your temps seem to go up and down day to day.) Every day you get a bigger glimpse of the big picture pattern of your cycle, so just keep recording temps and you will start detecting the pattern.
  • Each day gives you a new data point for your chart. Every day matters.
  • Consistency is key – establish a habit. It can take some time to get used to doing anything new in your life. So I recommend you set an intention to take your temp every day, especially when you’re just getting started. Before you know it, it will become second nature for you and just an automatic part of your morning.
  • IT’S OKAY if you miss a day or two. Repeat: it’s OK. Don’t give up on charting just because you miss one day here or there. Just jump right back in the next day! Everything you are observing is useful to seeing what’s going on with your body and it will still help you in the overall interpretation.

same time, same place

  • Take your temp at the same time every morning. Try to be consistent to within 30 mins. The reason for this is our bodies operate on a circadian rhythm and your body temperature will naturally rise as the day goes on until it reaches its peak (the typical standard is 98.6 deg F). You want to compare daily temperature measurements taken at roughly the same place on your own internal circadian clock.
  • If you wake up later than usual still take your temp anyway – and be sure to write down what time. You can always discount this temperature reading later if it seems to be inconsistent with those immediately before or after it. But having that data point is still useful, and still helps you in establishing the habit.
  • Take your temp by placing the thermometer under your tongue. [You could also take your temperature vaginally or rectally, but who wants to do that every morning? Note that the fancy forehead thermometers are generally not accurate enough for fertility charting.] The key is to choose one type and stick to it during your entire cycle. If you decide you want to switch thermometers I recommend waiting until the start of your next cycle so that you have the most consistent info possible for interpreting your chart.

use a basal body thermometer, not a regular digital one

  • Ultimately, you’re trying to detect a body temp change of 0.4 degrees F. Will a plain digital thermometer work? Maybe. But to give yourself the clearest picture of your cycle, accuracy is key. Basal thermometers are typically accurate to within ±0.01 degrees.
  • Price tags on basal thermometers vary. An inexpensive one ($8 from a local drugstore) will absolutely work – just make sure it is labelled “basal thermometer” vs digital thermometer. Pricier ones come with various features that may or may not be of interest to you. It comes down to personal preference on this one. I like to have the backlight and the memory function that comes with those typically offered in the $20-30 range. My current personal favorite is this one. There is also a slightly cheaper version by the same brand. If you’re into gadgets there are newer (way more expensive!) thermometers that sync your temp data straight to your phone. They do seem to get good reviews, so that is always another option.

take your temp before you get out of bed

  • Your goal is to find out your waking temperature.
  • Don’t get up, don’t go pee, just pop in your thermometer first thing while you’re still lying in bed.
  • Definitely don’t drink water or eat anything before taking your temp! (that might be obvious?)
  • You can even go back to sleep after getting the temp reading (that’s what I do!) – and if you have a thermometer that saves the temp data in memory you don’t even have to write it down immediately, just be sure to get it recorded before the end of the day.

have your partner help you with the temperature taking

  • Taking your temperature every morning is a (fun?) way your partner can help you and get involved in understanding your cycles.
  • My husband is in charge of the temperatures & he is the one who records it in the app every morning.
  • He is a total morning person, by every definition. He wakes up super early at 5am and is out the door for work by 5:15. So he takes my temp at about 5:05am every day. I am the complete opposite of a morning person, by every definition. I roll over just long enough for him to hand me the thermometer and as soon as it beeps I go right back to sleep.
  • On weekends he sometimes sleeps in a little later and just notes the time my temp is taken. Admittedly we are meticulous about this and I have found that it’s really not difficult once you get into the habit. We both agree that the benefits of having such detailed knowledge of my cycles far outweigh the slight disturbances in sleep.

just know that there is a way

  • Some women have irregular daily schedules or work evening shifts. If that’s you I want to reassure you that NFP is still possible for you. I’ve been there myself.
  • Lastly, if you find taking your temps at around the same time every day is stressing you out send me a note and we can brainstorm a solution that works for you in your life. I just urge you not to let any frustrations surrounding temperature taking hold you back. Hit me up, we can find a way!

So there you have it: a few of my suggestions on getting started with daily temperature taking. Let me know your thoughts and please do share any questions or concerns.

Don’t forget to grab your free guide, just click here.