Week 1 in 166

WEEK
1

This week starts on Sunday, December 29, 165 and ends on Saturday, January 4, 166.

WEEK EUROPE & ISO
1

This week starts on Monday, December 30, 165 and ends on Sunday, January 5, 166.

Week 1 of 166 spans the turn of the year: it begins on December 30, 165 and ends on January 5, 166.

Weeks since this week: 97089

Week 1 of 166 at a glance

Starts (Monday)December 30, 165
Ends (Sunday)January 5, 166
US week (Sunday to Saturday)1 (December 29, 165)
MonthDecember / January
QuarterQ1
Year completed at the end of this week1.4%
Weeks left in 166 after this week51
Weeks in 16652
Even or odd weekOdd

Calendar for December 166

December 166
SuMoTuWeThFrSa
Week 49123456
Week 5078910111213
Week 5114151617181920
Week 5221222324252627
Week 128293031
USA Calendar

Download Calendar in printable A4 PDF

  • Print December 166 Calendar Open calendar PDF in new window (US version)
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  • Print Full Year 166 Calendar (US version) Open calendar PDF in new window
  • Print Full Year 166 Calendar (EU/ISO Version) Open calendar PDF in new window

    • All Weeks in 166:

    Week 1 in 166 Week 2 in 166 Week 3 in 166 Week 4 in 166 Week 5 in 166 Week 6 in 166 Week 7 in 166 Week 8 in 166 Week 9 in 166 Week 10 in 166 Week 11 in 166 Week 12 in 166 Week 13 in 166 Week 14 in 166 Week 15 in 166 Week 16 in 166 Week 17 in 166 Week 18 in 166 Week 19 in 166 Week 20 in 166 Week 21 in 166 Week 22 in 166 Week 23 in 166 Week 24 in 166 Week 25 in 166 Week 26 in 166 Week 27 in 166 Week 28 in 166 Week 29 in 166 Week 30 in 166 Week 31 in 166 Week 32 in 166 Week 33 in 166 Week 34 in 166 Week 35 in 166 Week 36 in 166 Week 37 in 166 Week 38 in 166 Week 39 in 166 Week 40 in 166 Week 41 in 166 Week 42 in 166 Week 43 in 166 Week 44 in 166 Week 45 in 166 Week 46 in 166 Week 47 in 166 Week 48 in 166 Week 49 in 166 Week 50 in 166 Week 51 in 166 Week 52 in 166

    Past & Future Week Number 1:

    Week 1 in 2016 Week 1 in 2017 Week 1 in 2018 Week 1 in 2019 Week 1 in 2020 Week 1 in 2021 Week 1 in 2022 Week 1 in 2023 Week 1 in 2024 Week 1 in 2025 Week 1 in 2026 Week 1 in 2027 Week 1 in 2028 Week 1 in 2029 Week 1 in 2030 Week 1 in 2031 Week 1 in 2032 Week 1 in 2033 Week 1 in 2034 Week 1 in 2035 Week 1 in 2036

    US and ISO week numbers

    In the US system, where weeks start on Sunday and week 1 is the week that contains 1 January, this is week 1 of 166. It runs from December 29, 165 to January 4, 166.

    Even and odd weeks

    Week 1 is an odd week. Even and odd week numbers are used for alternating schedules such as shift rotas, school timetables, custody arrangements and waste collection.

    Week 1 in other years

    FromTo
    Week 1 in 164January 2, 164January 8, 164
    Week 1 in 165December 31, 164January 6, 165
    Week 1 in 167December 29, 166January 4, 167
    Week 1 in 168January 4, 168January 10, 168

    How week numbers are counted

    Most of the world numbers weeks according to the ISO 8601 standard. A week starts on Monday, and week 1 is the week that contains the first Thursday of the year, which is always the week that contains 4 January.

    Week 1 of 166 began on December 30, 165. 166 has 52 ISO weeks.

    Because of this rule, the first days of January can belong to the last week of the previous year, and the last days of December can belong to week 1 of the next year.

    In the United States, weeks usually start on Sunday and week 1 is the week that contains 1 January, so the US week number can differ from the ISO week number.

    Find the week number of a date

    Frequently Asked Questions (FAQ)

    When does week 1 of 166 start and end?

    Week 1 of 166 starts on December 30, 165 and ends on January 5, 166 (ISO 8601, Monday to Sunday).

    Which month is week 1 of 166 in?

    Week 1 of 166 starts in December and ends in January.

    What dates are in week 1 of 166?

    December 30, 165, December 31, 165, January 1, 166, January 2, 166, January 3, 166, January 4, 166, and January 5, 166

    How many weeks does 166 have?

    166 has 52 ISO weeks.

    Is week 1 an even or odd week?

    Week 1 is an odd week.

    What is the US week number for this week?

    In the US system, where weeks start on Sunday and week 1 is the week that contains 1 January, this is week 1 of 166. It runs from December 29, 165 to January 4, 166.