Thread by @dogemperor

So, a brief history of time...or at least daylight savings time...for those who may wonder "why do we even do DST, and why don't we just go to standard time"

(assuming you're not in non-tribal lands in AZ or Hawaii, that is)

1/x

https://twitter.com/elwasson/status/1456339567615873029

So the US did not actually (as a whole) do DST on a national basis until 1918, and contrary to the old yarn that it was meant to help farmers...the first DST law was a wartime measure to conserve coal (and only lasted for two years).

en.wikipedia.org/wiki/Standard_…

2/x

And as it was, farmers actually *DESPISED* DST (because it threw their schedules off, and those of their livestock), so despite what Woodrow Wilson wanted, it went away and stayed away until World War II.

When WWII came around, we ended up with year-round DST;

3/x

it was called "War Time", and implemented...not just to save fuel, but to prevent people from having to travel in a blackout (you had a lot of shift work in the war, and blackout restrictions were in place in much of the US):

defense.gov/News/Feature-S…

4/x

Even cars had to abide by blackout restrictions, with very low power headlamps (there was a real concern bombers could target based on car traffic), as this MUTCD (a manual of traffic safety) from 1942 shows from p 184 on:

5/x

ghawkins.engr.tamu.edu/wp-content/upl…

After the war ended, some states did DST, some did not, some parts of states did and others didn't, and they tended to do so at different times in the year; you also had additional complications that some areas (as TV started) actually shifted time zones...

6/x

to match up with national network feeds (Louisville, KY and surrounding areas being probably the most notorious example of a "TV time zone shift"; it was in Central Time until 1961) csmonitor.com/2000/0829/p2s2…

And in 1966, Congress got involved.

7/x

In 1966, Congress passed the Uniform Time Act, which mandated DST--though for quite a bit shorter than it is now (originally it was last Sunday in April through last Sunday in October). States could opt out as a whole, or for a single time zone.

en.wikipedia.org/wiki/Uniform_T…

8/x

While this didn't completely solve things (Indiana was a particular mess until 2006; in summer it functionally existed in *four* time zones, with DST in areas bordering Chicago and Louisville and Cincinnati and no DST in the "inland" Central and Eastern time zones)...

9/x

...for the most part, people were springing forward and falling back at the same time.

We had one other instance when year-round DST happened--1974 and part of 1975 had year-round DST as a trial as an emergency fuel conservation measure.

en.wikipedia.org/wiki/Daylight_…

10/x

In full context: The OPEC embargo had so heavily hit the US that there were plans to do the first formal rationing since World War II (and ration stamps were even printed) and gas purchases were severely limited in practice:

en.wikipedia.org/wiki/1973_oil_…

11/x

And this had actually seriously hit electric companies too (which at the time heavily used oil); there were actually requests to not string Christmas lights, the state of Oregon outright banned Christmas lights and commercial lighting...basically wartime conditions.

12/x

And after 1975, DST went back to the same late April-late October schedule until 1986, when DST was extended a month (based on claims that it decreased crime) under Reagan's administration...

13/x

...and then increased again in 2005, under the Energy Policy Act of 2005 (extending it to mid-March through early November). The claim was that DST reduced energy usage...

en.wikipedia.org/wiki/Daylight_…

14/x

although Indiana's switchover to DST showed an *increase* in energy consumption (less lighting, more heating/cooling), and the US Chamber of Commerce did let slip they liked the daylight hours for more shopping (which is probably just as much reason it passed).

15/x

And now there's a proposal to go to year-round DST again (despite the fact we're not at a state of war and it really doesn't save energy compared to other conservation measures) when it'd honestly make more sense to...just...don't spring forward *or* fall back.

16/x

(And there's parts of the US that don't bother with the DST thing...Arizona, Hawaii, Puerto Rico. They seem to do just fine.)

But if anyone is curious where it comes from--it's nothing to do with farmers, it's usually either wartime or other conservation involved.

17/end