joelgrant had an interesting comment to a post I wrote about three weeks ago, so I thought I’d bring the issue briefly to the top again. Folks who aren’t interested in civil time geekiness can ignore this.
Bill Seymour
Just another Freethought Blogs site
One of the difficulties with comparing local times in different regions is that the definition of local time is specified by the government in the locality, and governemnts change their mind a lot. I used to work for a company that dealt with data from all over the world, and we had to deal with this all the time. Internally, we did everything in UTC, so we had time zone files that the software used to convert to whatever time zone the user wanted. Every time the rules for a country changed, we had to send out new time zone files, which might take a month or two to get installed everywhere. The worst was Brazil, because they used DST, but the dates when DST started and ended were specified by an act of their government and changed every year. Moreover the government didn’t get around to deciding the dates until maybe a month or so before DST went into effect. So we were guarranteed that the local times would be off by an hour for a few weeks or months every year.