Im trying to translate the technical mB into "Stormy, Rain, Change, Fair and Dry" as you mention.. This is for mostly home use. The ASOS 5 minute files are now available via FTP for most stations so I have written code to pull these and display the information. I wanted to put a color background behind the mB reading that was color coded to the values above. But I need to know how to arrive at these numbers..
Maybe its a + - from a average from your location ? maybe its a devation over 24hrs ?
Maybe rete of change is a better way ??
I just cant find any info on how ALL the makers of barometer come up with the markings !
Kinda amazing that these are marked going way back in time, yet there seems to be nothing as guidence for these markings ?!?!