Empty local_timestamp in .FIT files

I’m indexing .FIT files downloaded from the website and noticed that the local_timestamp field is always 0. Is that something to be expected?

Seems normal. FYI, Garmin devices use this field for the same rides.

So I’m curious, it is possible to determine the timezone of the ride without this field? Here I’m in GMT+2 but can’t find any information about it.

Couple of my Garmin activities below. I’m on NZT and couldn’t correlate the local_timestamp to a timezone but must be there somewhere I would think. Happy to send you a couple of my Garmin fit files if it helps.

Yeah so from Garmin you get the right information, I also have this field for Polar and Suunto. Usually I just compute a timezone offset just by substracting the timestamp with the local_timestamp and getting the diff in seconds.
However, when downloading directly the .FIT from Zwift, this field is 0 so I can’t.

From where did you download your file from Garmin? I can’t find the option on Garmin Connect.
I was getting the information from the Garmin API but they stopped recently forwarding the 3rd party data (Zwift included).

From …

… which is listed under your Activities

Yep, same with me.

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Hi @julien_B

It’s hard to answer your question because despite my supporting the Zwift app for a long time, I’ve never really been trained on how to modify .FIT files. Our support team actually doesn’t have the tools to view or edit .FIT files and we’re not authorized to use third-party resources for this either, so I can’t offer any official commentary.

Chances are this is the Zwift .FIT file displaying as intended.

I do, however, see a bug report number attached to this Forums thread, so there’s something about this issue which is being investigated by Zwift’s developers.


Hey all, this bug has been fixed in game version 1.27.0 which released today. Please update Zwift at your earliest convenience and let us know if everything’s working as it should now (or not). Thanks for your patience.

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Hi Shuji,

Sorry for the delay in the response. I did a test with the version 1.28.0 (101433), and it seems the local_timestamp is still 0.