"Permanent" DST

Owen DeLong owen at delong.com
Wed Mar 16 16:04:43 UTC 2022

> "My flight leaves at 6 AM local time and lasts 90 minutes, but I'm crossing 3 timezones heading west...so you need to pick me up at...uh....4:30 AM your time?  Oh wait....are you currently in DST or not because we don't do DST here, but I think you do....so you either need to pick me up at 4:30 AM or 3:30 AM...I'm not sure....what's your time is it now?  Ok, it's 5 AM my time and 7 AM your time, so no DST, so...uh...but next week your zone is switching to DST but we're already on it..."

Um, if you manage to cross 3 timezones in 90 minutes, you have a VERY fast aircraft or you are really far north.

Most jet airliners max out somewhere approximating 500 statute MPH (actually a little less) not accounting for wind.

Going west, you’re usually against the wind (northern hemisphere, you’re with the wind in the southern hemisphere).

At the equator, timezones are roughly 1,000 miles (technically 1037.56) wide (earth has a roughly 8,000 mile diameter for an approximately 24,000 mile circumference).
Obviously, they get narrower as you get farther from the equator, but not linearly so. At 45º Latitude, this becomes 733.84 SM. 
The half-width point is approximately 60º latitude (518.97 SM).

To put some perspective on this, Portland, OR is roughly 45º North. Seattle, WA is roughly 47º North. To get to 60º N, you’re looking at such densely populated locales as Whitehorse, Yukon Territory (60.72º North). Whitehorse is (by far) the largest city in the entire Yukon Territory. Admittedly, St. Petersburg, RU is also very close to 60º North and a bit more populous. Coincidentally, 60º latitude. To put this in some additional perspective, the arctic and antarctic circles are at approximately 66.5º latitude. Those circles approximately enclose the areas where the sun does not set within 24 hours of the summer solstice. (The actual phenomenon is a little larger due to refraction).

I’m not sure if there are direct flights between (e.g. Winnipeg and Whitehorse), but that’s an example of a city pair that would be necessary to do a 90 minute flight crossing 3 timezones going west, assuming no wind at altitude, though Winnipeg is a bit of a fudge since it’s only 49.9º latitude).

I couldn’t find a place outside of Antarctica that was wide enough to have 3 timezones at 60º Latitude. Australia came closest, but Adelaide is only 34.93º South.

I don’t think there are two airports at that spacing on Antarctica, either.

There might be feasible options in Europe. Perhaps Reykjavik to Oslo  or Stockholm might do the trick.

Nonetheless, your point about timezone absurdity and flight calculations is well taken. Daylight Stupid Time (and the some do/some don’t and on a variety of schedules) doesn’t make it any easier, either.

> vs
> "My flight leaves at 06:00 zulu, lasts 90 minutes, so I'm landing at 7:30 zulu.  See you then."
> For the record, I was always told DST was implemented because of farmers.
> I'm a farmer and I hate timezones.  I just wake up when the rooster starts crowing, and no one goes out to adjust him twice a year for DST.

I would definitely favor flights operating and/or publishing their schedules in UTC rather than local times. (or at least having the UTC times available adjacent to the local times).

I’m not opposed to the idea of switching everyone to UTC and letting “9 to 5” become “X to Y” depending on location, but I suspect that would break too many people’s brains to ever gain wide acceptance from the majority of voters that would have to approve such a thing.

Heck, California couldn’t even figure out that it was a good idea to vote to get rid of Daylight Stupid Time. (Note, by get rid, I am not advocating for being PST all year. I don’t care whether we go PST or MST all year, I just want to pick one time zone for the entire year and stop jumping back and forth for reasons utterly passing understanding).


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