WKNOTEST.TXT J R Stockton >= 2008-09-12 (c) www.merlyn.demon.co.uk Correspondence of Gregorian Date and ISO-8601 Week Numbering. The pattern repeats exactly at 28-year intervals, except where broken by missing Leap Years. Four Tables. YYYY-MM-DD = YYYY-WW-D 1999-12-27 - 1999 52 1 1999-12-28 - 1999 52 2 1999-12-29 - 1999 52 3 1999-12-30 - 1999 52 4 1999-12-31 - 1999 52 5 2000-01-01 - 1999 52 6 2000-01-02 - 1999 52 7 2000-01-03 - 2000 01 1 2000-01-04 - 2000 01 2 2000-01-05 - 2000 01 3 2000-01-06 - 2000 01 4 2000-01-07 - 2000 01 5 2000-01-08 - 2000 01 6 2000-01-09 - 2000 01 7 2000-12-25 - 2000 52 1 2000-12-26 - 2000 52 2 2000-12-27 - 2000 52 3 2000-12-28 - 2000 52 4 2000-12-29 - 2000 52 5 2000-12-30 - 2000 52 6 2000-12-31 - 2000 52 7 2001-01-01 - 2001 01 1 2001-01-02 - 2001 01 2 2001-01-03 - 2001 01 3 2001-01-04 - 2001 01 4 2001-01-05 - 2001 01 5 2001-01-06 - 2001 01 6 2001-01-07 - 2001 01 7 2001-12-24 - 2001 52 1 2001-12-25 - 2001 52 2 2001-12-26 - 2001 52 3 2001-12-27 - 2001 52 4 2001-12-28 - 2001 52 5 2001-12-29 - 2001 52 6 2001-12-30 - 2001 52 7 2001-12-31 - 2002 01 1 2002-01-01 - 2002 01 2 2002-01-02 - 2002 01 3 2002-01-03 - 2002 01 4 2002-01-04 - 2002 01 5 2002-01-05 - 2002 01 6 2002-01-06 - 2002 01 7 2002-12-23 - 2002 52 1 2002-12-24 - 2002 52 2 2002-12-25 - 2002 52 3 2002-12-26 - 2002 52 4 2002-12-27 - 2002 52 5 2002-12-28 - 2002 52 6 2002-12-29 - 2002 52 7 2002-12-30 - 2003 01 1 2002-12-31 - 2003 01 2 2003-01-01 - 2003 01 3 2003-01-02 - 2003 01 4 2003-01-03 - 2003 01 5 2003-01-04 - 2003 01 6 2003-01-05 - 2003 01 7 2003-12-22 - 2003 52 1 2003-12-23 - 2003 52 2 2003-12-24 - 2003 52 3 2003-12-25 - 2003 52 4 2003-12-26 - 2003 52 5 2003-12-27 - 2003 52 6 2003-12-28 - 2003 52 7 2003-12-29 - 2004 01 1 2003-12-30 - 2004 01 2 2003-12-31 - 2004 01 3 2004-01-01 - 2004 01 4 2004-01-02 - 2004 01 5 2004-01-03 - 2004 01 6 2004-01-04 - 2004 01 7 2004-12-20 - 2004 52 1 2004-12-21 - 2004 52 2 2004-12-22 - 2004 52 3 2004-12-23 - 2004 52 4 2004-12-24 - 2004 52 5 2004-12-25 - 2004 52 6 2004-12-26 - 2004 52 7 2004-12-27 - 2004 53 1 2004-12-28 - 2004 53 2 2004-12-29 - 2004 53 3 2004-12-30 - 2004 53 4 2004-12-31 - 2004 53 5 2005-01-01 - 2004 53 6 2005-01-02 - 2004 53 7 2005-01-03 - 2005 01 1 2005-01-04 - 2005 01 2 2005-01-05 - 2005 01 3 2005-01-06 - 2005 01 4 2005-01-07 - 2005 01 5 2005-01-08 - 2005 01 6 2005-01-09 - 2005 01 7 2005-12-26 - 2005 52 1 2005-12-27 - 2005 52 2 2005-12-28 - 2005 52 3 2005-12-29 - 2005 52 4 2005-12-30 - 2005 52 5 2005-12-31 - 2005 52 6 2006-01-01 - 2005 52 7 2006-01-02 - 2006 01 1 2006-01-03 - 2006 01 2 2006-01-04 - 2006 01 3 2006-01-05 - 2006 01 4 2006-01-06 - 2006 01 5 2006-01-07 - 2006 01 6 2006-01-08 - 2006 01 7 2006-12-25 - 2006 52 1 2006-12-26 - 2006 52 2 2006-12-27 - 2006 52 3 2006-12-28 - 2006 52 4 2006-12-29 - 2006 52 5 2006-12-30 - 2006 52 6 2006-12-31 - 2006 52 7 2007-01-01 - 2007 01 1 2007-01-02 - 2007 01 2 2007-01-03 - 2007 01 3 2007-01-04 - 2007 01 4 2007-01-05 - 2007 01 5 2007-01-06 - 2007 01 6 2007-01-07 - 2007 01 7 2007-12-24 - 2007 52 1 2007-12-25 - 2007 52 2 2007-12-26 - 2007 52 3 2007-12-27 - 2007 52 4 2007-12-28 - 2007 52 5 2007-12-29 - 2007 52 6 2007-12-30 - 2007 52 7 2007-12-31 - 2008 01 1 2008-01-01 - 2008 01 2 2008-01-02 - 2008 01 3 2008-01-03 - 2008 01 4 2008-01-04 - 2008 01 5 2008-01-05 - 2008 01 6 2008-01-06 - 2008 01 7 2008-12-22 - 2008 52 1 2008-12-23 - 2008 52 2 2008-12-24 - 2008 52 3 2008-12-25 - 2008 52 4 2008-12-26 - 2008 52 5 2008-12-27 - 2008 52 6 2008-12-28 - 2008 52 7 2008-12-29 - 2009 01 1 2008-12-30 - 2009 01 2 2008-12-31 - 2009 01 3 2009-01-01 - 2009 01 4 2009-01-02 - 2009 01 5 2009-01-03 - 2009 01 6 2009-01-04 - 2009 01 7 2009-12-21 - 2009 52 1 2009-12-22 - 2009 52 2 2009-12-23 - 2009 52 3 2009-12-24 - 2009 52 4 2009-12-25 - 2009 52 5 2009-12-26 - 2009 52 6 2009-12-27 - 2009 52 7 2009-12-28 - 2009 53 1 2009-12-29 - 2009 53 2 2009-12-30 - 2009 53 3 2009-12-31 - 2009 53 4 2010-01-01 - 2009 53 5 2010-01-02 - 2009 53 6 2010-01-03 - 2009 53 7 2010-01-04 - 2010 01 1 2010-01-05 - 2010 01 2 2010-01-06 - 2010 01 3 2010-01-07 - 2010 01 4 2010-01-08 - 2010 01 5 2010-01-09 - 2010 01 6 2010-01-10 - 2010 01 7 2010-12-27 - 2010 52 1 2010-12-28 - 2010 52 2 2010-12-29 - 2010 52 3 2010-12-30 - 2010 52 4 2010-12-31 - 2010 52 5 2011-01-01 - 2010 52 6 2011-01-02 - 2010 52 7 2011-01-03 - 2011 01 1 2011-01-04 - 2011 01 2 2011-01-05 - 2011 01 3 2011-01-06 - 2011 01 4 2011-01-07 - 2011 01 5 2011-01-08 - 2011 01 6 2011-01-09 - 2011 01 7 2011-12-26 - 2011 52 1 2011-12-27 - 2011 52 2 2011-12-28 - 2011 52 3 2011-12-29 - 2011 52 4 2011-12-30 - 2011 52 5 2011-12-31 - 2011 52 6 2012-01-01 - 2011 52 7 2012-01-02 - 2012 01 1 2012-01-03 - 2012 01 2 2012-01-04 - 2012 01 3 2012-01-05 - 2012 01 4 2012-01-06 - 2012 01 5 2012-01-07 - 2012 01 6 2012-01-08 - 2012 01 7 2012-12-24 - 2012 52 1 2012-12-25 - 2012 52 2 2012-12-26 - 2012 52 3 2012-12-27 - 2012 52 4 2012-12-28 - 2012 52 5 2012-12-29 - 2012 52 6 2012-12-30 - 2012 52 7 2012-12-31 - 2013 01 1 2013-01-01 - 2013 01 2 2013-01-02 - 2013 01 3 2013-01-03 - 2013 01 4 2013-01-04 - 2013 01 5 2013-01-05 - 2013 01 6 2013-01-06 - 2013 01 7 2013-12-23 - 2013 52 1 2013-12-24 - 2013 52 2 2013-12-25 - 2013 52 3 2013-12-26 - 2013 52 4 2013-12-27 - 2013 52 5 2013-12-28 - 2013 52 6 2013-12-29 - 2013 52 7 2013-12-30 - 2014 01 1 2013-12-31 - 2014 01 2 2014-01-01 - 2014 01 3 2014-01-02 - 2014 01 4 2014-01-03 - 2014 01 5 2014-01-04 - 2014 01 6 2014-01-05 - 2014 01 7 2014-12-22 - 2014 52 1 2014-12-23 - 2014 52 2 2014-12-24 - 2014 52 3 2014-12-25 - 2014 52 4 2014-12-26 - 2014 52 5 2014-12-27 - 2014 52 6 2014-12-28 - 2014 52 7 2014-12-29 - 2015 01 1 2014-12-30 - 2015 01 2 2014-12-31 - 2015 01 3 2015-01-01 - 2015 01 4 2015-01-02 - 2015 01 5 2015-01-03 - 2015 01 6 2015-01-04 - 2015 01 7 2015-12-21 - 2015 52 1 2015-12-22 - 2015 52 2 2015-12-23 - 2015 52 3 2015-12-24 - 2015 52 4 2015-12-25 - 2015 52 5 2015-12-26 - 2015 52 6 2015-12-27 - 2015 52 7 2015-12-28 - 2015 53 1 2015-12-29 - 2015 53 2 2015-12-30 - 2015 53 3 2015-12-31 - 2015 53 4 2016-01-01 - 2015 53 5 2016-01-02 - 2015 53 6 2016-01-03 - 2015 53 7 2016-01-04 - 2016 01 1 2016-01-05 - 2016 01 2 2016-01-06 - 2016 01 3 2016-01-07 - 2016 01 4 2016-01-08 - 2016 01 5 2016-01-09 - 2016 01 6 2016-01-10 - 2016 01 7 2016-12-26 - 2016 52 1 2016-12-27 - 2016 52 2 2016-12-28 - 2016 52 3 2016-12-29 - 2016 52 4 2016-12-30 - 2016 52 5 2016-12-31 - 2016 52 6 2017-01-01 - 2016 52 7 2017-01-02 - 2017 01 1 2017-01-03 - 2017 01 2 2017-01-04 - 2017 01 3 2017-01-05 - 2017 01 4 2017-01-06 - 2017 01 5 2017-01-07 - 2017 01 6 2017-01-08 - 2017 01 7 2017-12-25 - 2017 52 1 2017-12-26 - 2017 52 2 2017-12-27 - 2017 52 3 2017-12-28 - 2017 52 4 2017-12-29 - 2017 52 5 2017-12-30 - 2017 52 6 2017-12-31 - 2017 52 7 2018-01-01 - 2018 01 1 2018-01-02 - 2018 01 2 2018-01-03 - 2018 01 3 2018-01-04 - 2018 01 4 2018-01-05 - 2018 01 5 2018-01-06 - 2018 01 6 2018-01-07 - 2018 01 7 2018-12-24 - 2018 52 1 2018-12-25 - 2018 52 2 2018-12-26 - 2018 52 3 2018-12-27 - 2018 52 4 2018-12-28 - 2018 52 5 2018-12-29 - 2018 52 6 2018-12-30 - 2018 52 7 2018-12-31 - 2019 01 1 2019-01-01 - 2019 01 2 2019-01-02 - 2019 01 3 2019-01-03 - 2019 01 4 2019-01-04 - 2019 01 5 2019-01-05 - 2019 01 6 2019-01-06 - 2019 01 7 2019-12-23 - 2019 52 1 2019-12-24 - 2019 52 2 2019-12-25 - 2019 52 3 2019-12-26 - 2019 52 4 2019-12-27 - 2019 52 5 2019-12-28 - 2019 52 6 2019-12-29 - 2019 52 7 2019-12-30 - 2020 01 1 2019-12-31 - 2020 01 2 2020-01-01 - 2020 01 3 2020-01-02 - 2020 01 4 2020-01-03 - 2020 01 5 2020-01-04 - 2020 01 6 2020-01-05 - 2020 01 7 2020-12-21 - 2020 52 1 2020-12-22 - 2020 52 2 2020-12-23 - 2020 52 3 2020-12-24 - 2020 52 4 2020-12-25 - 2020 52 5 2020-12-26 - 2020 52 6 2020-12-27 - 2020 52 7 2020-12-28 - 2020 53 1 2020-12-29 - 2020 53 2 2020-12-30 - 2020 53 3 2020-12-31 - 2020 53 4 2021-01-01 - 2020 53 5 2021-01-02 - 2020 53 6 2021-01-03 - 2020 53 7 2021-01-04 - 2021 01 1 2021-01-05 - 2021 01 2 2021-01-06 - 2021 01 3 2021-01-07 - 2021 01 4 2021-01-08 - 2021 01 5 2021-01-09 - 2021 01 6 2021-01-10 - 2021 01 7 2021-12-27 - 2021 52 1 2021-12-28 - 2021 52 2 2021-12-29 - 2021 52 3 2021-12-30 - 2021 52 4 2021-12-31 - 2021 52 5 2022-01-01 - 2021 52 6 2022-01-02 - 2021 52 7 2022-01-03 - 2022 01 1 2022-01-04 - 2022 01 2 2022-01-05 - 2022 01 3 2022-01-06 - 2022 01 4 2022-01-07 - 2022 01 5 2022-01-08 - 2022 01 6 2022-01-09 - 2022 01 7 2022-12-26 - 2022 52 1 2022-12-27 - 2022 52 2 2022-12-28 - 2022 52 3 2022-12-29 - 2022 52 4 2022-12-30 - 2022 52 5 2022-12-31 - 2022 52 6 2023-01-01 - 2022 52 7 2023-01-02 - 2023 01 1 2023-01-03 - 2023 01 2 2023-01-04 - 2023 01 3 2023-01-05 - 2023 01 4 2023-01-06 - 2023 01 5 2023-01-07 - 2023 01 6 2023-01-08 - 2023 01 7 2023-12-25 - 2023 52 1 2023-12-26 - 2023 52 2 2023-12-27 - 2023 52 3 2023-12-28 - 2023 52 4 2023-12-29 - 2023 52 5 2023-12-30 - 2023 52 6 2023-12-31 - 2023 52 7 2024-01-01 - 2024 01 1 2024-01-02 - 2024 01 2 2024-01-03 - 2024 01 3 2024-01-04 - 2024 01 4 2024-01-05 - 2024 01 5 2024-01-06 - 2024 01 6 2024-01-07 - 2024 01 7 2024-12-23 - 2024 52 1 2024-12-24 - 2024 52 2 2024-12-25 - 2024 52 3 2024-12-26 - 2024 52 4 2024-12-27 - 2024 52 5 2024-12-28 - 2024 52 6 2024-12-29 - 2024 52 7 2024-12-30 - 2025 01 1 2024-12-31 - 2025 01 2 2025-01-01 - 2025 01 3 2025-01-02 - 2025 01 4 2025-01-03 - 2025 01 5 2025-01-04 - 2025 01 6 2025-01-05 - 2025 01 7 2025-12-22 - 2025 52 1 2025-12-23 - 2025 52 2 2025-12-24 - 2025 52 3 2025-12-25 - 2025 52 4 2025-12-26 - 2025 52 5 2025-12-27 - 2025 52 6 2025-12-28 - 2025 52 7 2025-12-29 - 2026 01 1 2025-12-30 - 2026 01 2 2025-12-31 - 2026 01 3 2026-01-01 - 2026 01 4 2026-01-02 - 2026 01 5 2026-01-03 - 2026 01 6 2026-01-04 - 2026 01 7 2026-12-21 - 2026 52 1 2026-12-22 - 2026 52 2 2026-12-23 - 2026 52 3 2026-12-24 - 2026 52 4 2026-12-25 - 2026 52 5 2026-12-26 - 2026 52 6 2026-12-27 - 2026 52 7 2026-12-28 - 2026 53 1 2026-12-29 - 2026 53 2 2026-12-30 - 2026 53 3 2026-12-31 - 2026 53 4 2027-01-01 - 2026 53 5 2027-01-02 - 2026 53 6 2027-01-03 - 2026 53 7 2027-01-04 - 2027 01 1 2027-01-05 - 2027 01 2 2027-01-06 - 2027 01 3 2027-01-07 - 2027 01 4 2027-01-08 - 2027 01 5 2027-01-09 - 2027 01 6 2027-01-10 - 2027 01 7 2027-12-27 - 2027 52 1 2027-12-28 - 2027 52 2 2027-12-29 - 2027 52 3 2027-12-30 - 2027 52 4 2027-12-31 - 2027 52 5 2028-01-01 - 2027 52 6 2028-01-02 - 2027 52 7 2028-01-03 - 2028 01 1 2028-01-04 - 2028 01 2 2028-01-05 - 2028 01 3 2028-01-06 - 2028 01 4 2028-01-07 - 2028 01 5 2028-01-08 - 2028 01 6 2028-01-09 - 2028 01 7 2028-12-25 - 2028 52 1 2028-12-26 - 2028 52 2 2028-12-27 - 2028 52 3 2028-12-28 - 2028 52 4 2028-12-29 - 2028 52 5 2028-12-30 - 2028 52 6 2028-12-31 - 2028 52 7 2029-01-01 - 2029 01 1 2029-01-02 - 2029 01 2 2029-01-03 - 2029 01 3 2029-01-04 - 2029 01 4 2029-01-05 - 2029 01 5 2029-01-06 - 2029 01 6 2029-01-07 - 2029 01 7 The above was generated by Javascript, YMDtoYWD and ISOlocaldateStr being in my file include3.js; copy into my js-demos.htm#Ev and press Eval : D = new Date(1999, 11, 1) for (j=0; j<365*30; j++) { D.setDate(D.getDate()+1) A = YMDtoYWD(D.getFullYear(), D.getMonth()+1, D.getDate()) if ((A[1]<2) || (A[1]>51)) document.writeln( D.ISOlocaldateStr(), ' - ', A[0], ' ', LZ(A[1]), ' ', A[2], '
') if ((A[1]==5) && (A[2]==3)) document.writeln('
') } The following was extracted by DOS find, to show Starts of calendar Year : 2000-01-01 - 1999 52 6 2001-01-01 - 2001 01 1 2002-01-01 - 2002 01 2 2003-01-01 - 2003 01 3 2004-01-01 - 2004 01 4 2005-01-01 - 2004 53 6 2006-01-01 - 2005 52 7 2007-01-01 - 2007 01 1 2008-01-01 - 2008 01 2 2009-01-01 - 2009 01 4 2010-01-01 - 2009 53 5 2011-01-01 - 2010 52 6 2012-01-01 - 2011 52 7 2013-01-01 - 2013 01 2 2014-01-01 - 2014 01 3 2015-01-01 - 2015 01 4 2016-01-01 - 2015 53 5 2017-01-01 - 2016 52 7 2018-01-01 - 2018 01 1 2019-01-01 - 2019 01 2 2020-01-01 - 2020 01 3 2021-01-01 - 2020 53 5 2022-01-01 - 2021 52 6 2023-01-01 - 2022 52 7 2024-01-01 - 2024 01 1 2025-01-01 - 2025 01 3 2026-01-01 - 2026 01 4 2027-01-01 - 2026 53 5 2028-01-01 - 2027 52 6 2029-01-01 - 2029 01 1 The following was extracted by DOS find, to show Starts of Week Ones : 2000-01-03 - 2000 01 1 2001-01-01 - 2001 01 1 2001-12-31 - 2002 01 1 2002-12-30 - 2003 01 1 2003-12-29 - 2004 01 1 2005-01-03 - 2005 01 1 2006-01-02 - 2006 01 1 2007-01-01 - 2007 01 1 2007-12-31 - 2008 01 1 2008-12-29 - 2009 01 1 2010-01-04 - 2010 01 1 2011-01-03 - 2011 01 1 2012-01-02 - 2012 01 1 2012-12-31 - 2013 01 1 2013-12-30 - 2014 01 1 2014-12-29 - 2015 01 1 2016-01-04 - 2016 01 1 2017-01-02 - 2017 01 1 2018-01-01 - 2018 01 1 2018-12-31 - 2019 01 1 2019-12-30 - 2020 01 1 2021-01-04 - 2021 01 1 2022-01-03 - 2022 01 1 2023-01-02 - 2023 01 1 2024-01-01 - 2024 01 1 2024-12-30 - 2025 01 1 2025-12-29 - 2026 01 1 2027-01-04 - 2027 01 1 2028-01-03 - 2028 01 1 2029-01-01 - 2029 01 1 The following shows coincident starts : 2001-01-01 - 2001 01 1 2007-01-01 - 2007 01 1 2018-01-01 - 2018 01 1 2024-01-01 - 2024 01 1 2029-01-01 - 2029 01 1 See my Web pages weekinfo.htm, js-date7.htm, js-nclds.htm, pas-time.htm; and mjd_date & dateprox via programs/00index.htm. -----