On Thu, 06 Feb 2020 14:27:40 -0000, charles wrote:

In article op.0fkjut2bwdg98l@glass,
Commander Kinsey wrote:
Why do barometers have different centre readings? I thought 1000 mbar was
average, as that's what barometers always used to have as the central
reading ("change"), but Wikipedia says it's 1013. I've seen some newer
ones with 1010 as the centre.

On mine it's 29.5 inches

Phwoar! ;-)

All mine have both measurements. It would appear it should be corrected for altitude, but that would mean a rotatable dial. I've got an app on my phone that does it, it'll be interesting to see if it changes the centre position with altitude, 1010 mbar is about right for here.