What can you do about time zone changes when charting your temperature using fertility awareness?

I have been travelling for 6 months now and since changing time zones my BBTs are no where near as low as they used to be at the start of the month and don’t rise much after ovulation. My cycle is an average 28 days and I have strong ovulation signs at day 14 but it is not reflected in my BBTs. So I guess my question is how long does it usually take for BBTs to adjust after radical time zone change and is there some kind of adjusting that can be done until it normalizes?

Changing time zones can be nerve wracking and infuriating at the same time when you are using the sympto-thermal method of fertility awareness and worried about the integrity of your temperatures, so I understand this question completely.

I want to mention some general things about traveling and time zones and also some specific things that I am pulling out from this question, too. Let me start with the general:

Time zones can be very annoying to switch because they do often have an affect on your temperatures. One hour doesn’t usually make a difference for almost anyone, but most people will see a drop or jump in their temperatures from a three hour change. Not only that, but if your sleep is completely different due to traveling you can have really obscured temps for a few days.

But it honestly isn’t that long lasting of an effect for most people. A good rule of thumb for when your temperatures should be normalized is when you aren’t feeling jet-lagged anymore.

Here is the good news, though: Your temperatures are not always important. In fact, there are only a few days of the cycle that they are extremely important, and otherwise you can just say “Darn, obscured temperature!” and leave it at that. If you do happen to have a time zone change on an important day, you still just say “Darn, obscured temperature!” The only difference is now you are not going to count that temperature towards anything like a post-peak/shift temperature count.

If you know the time zone change is going to come at an important time and you want to try to avoid obscured temperatures this is what you can do: Adjust your temperature time 1/2 hour towards when you will ultimately be temping in the new time zone enough days in advance that your last 1/2 hour change happens the day you get to the time zone. I know that sounds really confusing so here is an example:

You are going to travel from California to Florida. That means that if you took your temperature at 6am in California and at 6am in Florida your Florida temperature would be like a temperature you took 3 hours early in California (because when it’s 6am in Florida it’s 3am in California). Since 3 hours difference means you have to adjust 6 half-hours, you would need to start 5 days in advance to have the last half hour be at your normal wake up time in the new time zone. So…

Day -5: Temp at 5:30am
Day -4: Temp at 5:00am
Day -3: Temp at 4:30am
Day -2: Temp at 4:00am
Day -1: Temp at 3:30am
Day 0 (the first day you are waking up Florida): Temp at 6am

Obviously, looking at the example you can see that that option has MAJOR drawbacks when you are doing a big time zone change because you need a lot of days and you have to wake up earlier or later, which might not always be possible. You can also start the slow change when you get to your destination, especially if your wake up time is more flexible there.

But do you HAVE to do that if you don’t want to? NO. For most people a time zone jump will only affect them for the time they feel jet-lagged, so if that’s a day or two for you, so be it. All you have to do is remember that your temp is obscured and you should ALWAYS play it conservatively.

There are also now thermometer options that don’t rely on wake up time for temperature accuracy, like the temp drop*.

But now I want to get into a specific with this question

It seems that you are not just having a random jump or dip when you travel, but your temperatures have legitimately changed since starting to travel. I would explore whether that could be due to:

• Stress (psycho-emotional or physical from things like less sleep or a more poor quality of food from your norm)
• Being in a different climate
• A change in thermometer or something else

In general, time zones do make a difference, but if it’s not a few crazy “off” temperatures there is a good chance there is something else that is going on. I’d definitely recommend looking into anything that you think could have thrown off your hormones during your travels to see if you can figure out if it might have to do with your hormones or if it might be something like climate or your thermometer.

xoHannah

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