Apple watch altimeter issues

[Pono]

Here's some data that shows how far off a brand new Series 6 can be on altitude. The exact same running course was followed.

gain lowest elevation highest elevation
February 2nd 952 feet 461 feet 1420 feet
February 8th 945 feet 386 feet 1374 feet
February 13th 939 feet 614 feet 1560 feet

Clearly the relative change in altitude is a lot more accurate than the absolute altitude of the lowest and highest points. The gain only has an error of 1.3% versus the average of the three gain numbers. The 228 foot difference (614' - 386') in starting elevation is just totally unacceptable.
Some (many) of us bought this watch thinking that the altitude numbers themselves (not just the change or gain) would be accurate.

 

[Cheefy]

Mine was like that when it was new. I’ve had it nearly two months now and it is incredibly accurate every time. If the barometric pressure (local) has dropped much below 1000mbar the compass app elevation figure can be inaccurate but as soon as I start a GPS activity the elevation figures are spot on and pretty much identical for repeat runs. It’s the most accurate altimeter on any watch that I’ve had so far - way better than my Garmins. I just wish the HRM was better as it’s not as good or reliable as my Garmins.

 

[StumpyBloke]

OP, already a thread here:

Series 6 Altimeter Discrepancies

I’ve noticed today, possibly since the 7.0.1 update that the stock altimeter app shows a substantially different height to the My Altitude app. I know that the My Altitude app is correct because I’ve looked on Google Maps and it is exactly right for my location. There is about 10-15m difference...

forums.macrumors.com