Complications in Daylight Saving Time

Via Nelson’s Weblog, Daylight savings complications:

Twice a year as I set my clocks for daylight savings I wonder ‘isn’t it the future yet? Can’t computers do this for me?’ Then I remember the complexity that is the unix timezone database. 444k of datafiles (260k without comments) containing facts like ‘Louisville, KY didn’t observe daylight savings time in 1974.’
This spring, daylight savings time changes at 45 different times around the world. No wonder it’s so hard to know what time it is. “

I’ve blogged and struggled with this beast before.

Oh and it’s ” Daylight Saving Time”, no “s” as in ” “Daylight Savings Time”

Nelson points to a couple of new to me useful Links :

  • the unix timezone database, public-domain time zone database contains code and data that represent the history of local time for many representative locations around the globe and has links to other resources.
  • The Time and Date , with various bits for clock and calendar information

also be very careful Monday Morning as per: Springing ahead has its drawbacks:

In 1996 Prof. Coren did a study that was published in the New England Journal of Medicine that looked at car-crash data from Statistics Canada. He found there is about a 7 per cent increase in accidents the day after most of the country moves to daylight time.

Which also mentions another complication I hadn’t really thought about :

The official changeover happens at different times across the country: midnight in Newfoundland and New Brunswick, 3 a.m. in Manitoba and 2 a.m. everywhere else.

and Wired has Technology Resets the Clock with this gem at the end :

Ignoring daylight-saving time brings its own complications, though. In Indiana, 77 of the state’s 92 counties are in the Eastern time zone but do not change to daylight-saving time in April, except for two Indiana counties located near Cincinnati, Ohio and Louisville, Kentucky, which observe it.Counties in the northwest corner of Indiana (near Chicago) and the southwestern section (near Evansville) are in the Central time zone and also will be springing forward this Sunday with the rest of the nation.

“It’s kind of crazy. I work in one county and live in another so I spring forward and fall back on an almost daily basis,” said Jeff Cunner, a software programmer who lives near Indianapolis.

“My watch and cell phone reset themselves automatically, thankfully. Otherwise, I’d never know what time it is.”

and you think you have problems!


Joey has added on The Farm more Date and Time Calculation info inculding this

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