BSD-3-Clause licensed by Bjorn Buckwalter
Maintained by
This version can be pinned in stack with:leapseconds-announced-2017@sha256:8c4b2b3502815905ada91d114845b17eea4faaf8042de546dfe2490928447069,1415

Module documentation for 2017

Depends on 2 packages(full list with versions):


This libraray provides a static Data.Time.Clock.TAI.LeapSecondTable “containing” the leap seconds announced at library release time. A new version of the library is released every time the International Earth Rotation and Reference Systems Service (IERS) announces a new leap second at

This module is intended to provide a quick-and-dirty leap second solution for one-off analyses concerned only with the past and present (i.e. up until the next as of yet unannounced leap second), or for applications which can afford to be recompiled against an updated library as often as every six months.


Import Data.Time.Clock.AnnouncedLeapSeconds to bring the leap second table lst into scope. Here is a usage example:

import Data.Time
import Data.Time.Clock.TAI
import Data.Time.Clock.AnnouncedLeapSeconds

-- | Convert from UTC to TAI.
utcToTAITime' = utcToTAITime lst
-- | Convert from TAI to UTC.
taiToUTCTime' = taiToUTCTime lst

-- | Add a length of time to a UTC time, respecting leap seconds
--   (as opposed to Data.Time.Clock.addUTCTime).
addUTCTime' :: DiffTime -> UTCTime -> UTCTime
addUTCTime' dt = taiToUTCTime' . addAbsoluteTime dt . utcToTAITime'


2015.0.1 (2015-05)

  • Fix documentation to reflect addition of 2015 leap second.
  • Hide hypothetical leap seconds (prior to 1972-01-01).
  • Add test suite to .cabal.

2015 (2015-01)

  • Added 2015 leap second (2015-06-30T23:59:60Z).

2012 (2012-01)

  • Added 2012 leap second (2012-06-30T23:59:60Z).

2009 (2009-01)

Initial release including all leap seconds up to 2009-01-01.