[tz] Japanese Summer time fallback transition in autumn 2020?

horonet at ml.nict.go.jp horonet at ml.nict.go.jp
Tue Sep 18 06:00:36 UTC 2018

Dear Sirs,

Thank you for your email dated September 12, 2018.
We really appreciate your interest and comment.
Unfortunately, we have no information on the official name of additional 
hours past the 12th o'clock midnight on the last DST day of Japan.
If you ask NAOJ, you may be able to get more information.

NAOJ and NAOJ Ephemeris Computation Office's Websites:

Thank you for another question about DST in 2020.
The government is considering future DST in Japan, but nothing has been 
decided yet.

Thank you for your understanding.
We wish good luck to you.


Japan Standard Time Group
Space-Time standards Laboratory
Applied Electromagnetic Research Institute
National Institute of Information and Communications Technology

On 2018/09/12 2:00, Paul Eggert wrote:
> One other thing. The Japanese government is considering adopting
> daylight saving time for the 2020 Tokyo Olympics. Will this issue about
> 25-hour (or 26-hour) days come up in 2020? For example, could there be a
> 26-hour day in September 2020 with times ranging from 00:00 to 26:00? If
> so, a *lot* of computers will have to be reprogrammed, as no software
> I'm aware of supports timestamps like that now.

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