I go running most days and currently use a Fitbit Charge 3 (soon to be upgraded, but that’s another post) to track my run, uploading my progress to Strava. Recently I have noticed that I often receive a battery charging error half-way through my run causing the Fitbit to fail and not track any data. On looking at the issue in more detail its usually when the weather is very cold, on those early frosty mornings when its yet to get above minus numbers.
According to the Fitbit website the device has a operating temperature window of -10° to 45°C which should be more than sufficient for my early morning runs, however it appears that anything below -3 seems to cause the error. I can get around the problem either by tucking the device inside the sleeve of my fleece to keep it warm or tracking the run directly through Strava on my phone as a backup, but this will certainly influence my choice when looking for a new fitness tracker. From looking at feedback from other users of the device it also appears to problem on very hot days, although perhaps I have yet to experience this as I normally try to run in the coolest part of the day during the summer.