[tz] Tzdb and the Sunshine Protection Act

Brooks Harris brooks at edlmax.com
Thu Mar 2 22:22:29 UTC 2023

You've seen the Sunshine Protection Act is back:
Congress to consider making daylight saving time permanent

As I read the law it would shift STDOFF by an hour, for example, 
America/New_York would move to -04:00 STDOFF, essentially moving 
"Eastern Time" into the Atlantic time zone. Historically tzdb has 
honored the laws as faithfully as possible so that might be the right 
approach. But it seems to me this would be technically disruptive, 
necessitating a great deal of careful modification of existing 

The other method is to shift DST rules to "permanent" DST. The law might 
arguably be interpreted this way. That might be less disruptive and 
leave the option of returning to DST when its no longer "permanent", as 
happened in the 1970s.

There are many arguments for going to "permanent standard time" instead. 
One reason not mentioned is that it would be technically much easier and 
less disruptive.

How will tzdb manage this?

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