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Apple Watch in Cold Weather

Nov 29, 2020

For the last month I have been living the multiple watch lifestyle: Garmin Forerunner 245 for my runs and my Apple Watch for everything else. I outlined the reason for this in my post Apple Health data considerations with Garmin Forerunner and an Apple Watch and then documented how you can still consolidate the data into Apple Health in my post Manually Add Data Points to Apple Health.

It worked fine but it resulted in difficulties closing my Fitness rings - especially the Move goal. It’s getting colder but on one particular where I knew it was going to be a struggle to do my run and close the Move goal I rolled the dice and went out with my Apple Watch.

I had always suspected there were a couple things going on when the watch would turn off and go into Power Reserve with a reported 10% battery life:

  1. Weather was cold
  2. The watch drew a lot of power (received a phone call or connected to Cellular)

When I went out I turned the watch onto Airplane mode. The battery was 95%+. I ran about 6 miles and I made it through the run. However, once I stopped the run and was walking back to my house I turned off Airplane mode and within a few seconds the watch restarted and went into Power Reserve. I didn’t see what the battery was, but this seemed to confirm the problem and offered a remedy.

Since that day I went out twice more. The next day was a little warmer (35 degrees) and did not restart.

The following day I did get it to restart.

  • The temperature was 30 degrees at the start of the run
  • The watch was 100% at the beginning
  • I ran 8 miles and stopped the activity with the battery showing 87%
  • I turned off Airplane mode and immediately the battery dropped to 86% then 85% and then it restarted
  • Upon restart the battery showed 10%

I suspect any temperature under 30 degrees will cause a restart after turning off Airplane mode. I think I can live with this for now. If things get worse I still have the Forerunner 245.