[tz] Bulletin C number 58

Brian Inglis Brian.Inglis at SystematicSw.ab.ca
Sat Jul 6 16:47:12 UTC 2019

On 2019-07-04 17:15, Chris Woodbury via tz wrote:
> Christian Bizouard has struck again (and exactly a week earlier than I was expecting).

IERS have been getting quicker at announcing no change during the first week of
July, but January and adding leap seconds have been later and less consistent.

> No new leap-second.  I predict (after a careful perusal of Bulletin A) that we will see
> one in July 2020.  i.e.: 3802550400 38 # 1 Jul 2020

The Bulletin A dUT1 prediction for 2020 July is only -0.39s and the rate about
-0.01s/month, so if the rate does not increase much, dUT1 would only be about
-0.45s in 2020 Dec, and -0.51s in 2021 July.
That would suggest the next leap is more likely 3834086400 38 # 1 Jul 2021 MJD
59396 Unix @1625097600.

If one happens in 2020, that would follow recent trends of 2.5-3.5 years between
leaps, but if delayed until 2021, 2017 to 2021 would be the next largest gap
after that from 1999 to 2006.

Take care. Thanks, Brian Inglis, Calgary, Alberta, Canada

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