[LEAPSECS] next leap second

[John Sauter]

On Wed, 2017-01-11 at 13:07 +0000, Zefram wrote:
> John Sauter wrote:
> > While it is impossible to know for certain when the next leap
> > second
> > will occur, I predict it will be December 31, 2022.
> 
> I find that a surprising prediction.  What is your basis for it?
> 
> The extrapolating expression from the current Bulletin A
> <https://datacenter.iers.org/eop/-/somos/5Rgv/getTX/6/bulletina-xxx-0
> 01.txt>,
> which projects a linear evolution of UT2-TAI, suggests that UT1-TAI
> will approach -37.5 in early 2019 (actually passing it on 2019-02-
> 03),
> and then pass that value twice more early in the second half of 2019.
> So I'd expect the next leap second to happen on 2018-12-31 or 2019-
> 06-30.
> If there is no leap, this projection suggests that the UT1-UTC bound
> would
> be exceeded on 2020-01-19.  Extending all the way out to your
> proposed
> leap date, which is a dubious exercise given the crudity of the
> model,
> yields UT1-TAI ~= -39.228 at 2023-01-01, implying that we'd need to
> have
> two leaps between now and then, with 2022-12-31 being an early
> candidate
> for the *third* leap from now.
> 
> -zefram

Based on recent data from the IERS, I now think that the next leap
second will be on June 30, 2020, rather than December 31, 2020.
    John Sauter (John_Sauter at systemeyescomputerstore.com)
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