Week numbers 66

66 has 52 ISO weeks. Week 1: Jan 4 – 10 · Week 52: Dec 27, 66 – Jan 2, 67

66 at a glance

Weeks in 6652
Week 1January 4, 66 – January 10, 66
Week 52December 27, 66 – January 2, 67
Days in 66365
Leap yearNo

All Weeks in 66

Week From To Month
Week 1 in 66 January 4, 66 January 10, 66 January
Week 2 in 66 January 11, 66 January 17, 66 January
Week 3 in 66 January 18, 66 January 24, 66 January
Week 4 in 66 January 25, 66 January 31, 66 January
Week 5 in 66 February 1, 66 February 7, 66 February
Week 6 in 66 February 8, 66 February 14, 66 February
Week 7 in 66 February 15, 66 February 21, 66 February
Week 8 in 66 February 22, 66 February 28, 66 February
Week 9 in 66 March 1, 66 March 7, 66 March
Week 10 in 66 March 8, 66 March 14, 66 March
Week 11 in 66 March 15, 66 March 21, 66 March
Week 12 in 66 March 22, 66 March 28, 66 March
Week 13 in 66 March 29, 66 April 4, 66 March / April
Week 14 in 66 April 5, 66 April 11, 66 April
Week 15 in 66 April 12, 66 April 18, 66 April
Week 16 in 66 April 19, 66 April 25, 66 April
Week 17 in 66 April 26, 66 May 2, 66 April / May
Week 18 in 66 May 3, 66 May 9, 66 May
Week 19 in 66 May 10, 66 May 16, 66 May
Week 20 in 66 May 17, 66 May 23, 66 May
Week 21 in 66 May 24, 66 May 30, 66 May
Week 22 in 66 May 31, 66 June 6, 66 May / June
Week 23 in 66 June 7, 66 June 13, 66 June
Week 24 in 66 June 14, 66 June 20, 66 June
Week 25 in 66 June 21, 66 June 27, 66 June
Week 26 in 66 June 28, 66 July 4, 66 June / July
Week 27 in 66 July 5, 66 July 11, 66 July
Week 28 in 66 July 12, 66 July 18, 66 July
Week 29 in 66 July 19, 66 July 25, 66 July
Week 30 in 66 July 26, 66 August 1, 66 July / August
Week 31 in 66 August 2, 66 August 8, 66 August
Week 32 in 66 August 9, 66 August 15, 66 August
Week 33 in 66 August 16, 66 August 22, 66 August
Week 34 in 66 August 23, 66 August 29, 66 August
Week 35 in 66 August 30, 66 September 5, 66 August / September
Week 36 in 66 September 6, 66 September 12, 66 September
Week 37 in 66 September 13, 66 September 19, 66 September
Week 38 in 66 September 20, 66 September 26, 66 September
Week 39 in 66 September 27, 66 October 3, 66 September / October
Week 40 in 66 October 4, 66 October 10, 66 October
Week 41 in 66 October 11, 66 October 17, 66 October
Week 42 in 66 October 18, 66 October 24, 66 October
Week 43 in 66 October 25, 66 October 31, 66 October
Week 44 in 66 November 1, 66 November 7, 66 November
Week 45 in 66 November 8, 66 November 14, 66 November
Week 46 in 66 November 15, 66 November 21, 66 November
Week 47 in 66 November 22, 66 November 28, 66 November
Week 48 in 66 November 29, 66 December 5, 66 November / December
Week 49 in 66 December 6, 66 December 12, 66 December
Week 50 in 66 December 13, 66 December 19, 66 December
Week 51 in 66 December 20, 66 December 26, 66 December
Week 52 in 66 December 27, 66 January 2, 67 December / January

Calendars 66

January 66
MoTuWeThFrSaSu
Week 53123
Week 145678910
Week 211121314151617
Week 318192021222324
Week 425262728293031
February 66
MoTuWeThFrSaSu
Week 51234567
Week 6891011121314
Week 715161718192021
Week 822232425262728
March 66
MoTuWeThFrSaSu
Week 91234567
Week 10891011121314
Week 1115161718192021
Week 1222232425262728
Week 13293031
April 66
MoTuWeThFrSaSu
Week 131234
Week 14567891011
Week 1512131415161718
Week 1619202122232425
Week 172627282930
May 66
MoTuWeThFrSaSu
Week 1712
Week 183456789
Week 1910111213141516
Week 2017181920212223
Week 2124252627282930
Week 2231
June 66
MoTuWeThFrSaSu
Week 22123456
Week 2378910111213
Week 2414151617181920
Week 2521222324252627
Week 26282930
July 66
MoTuWeThFrSaSu
Week 261234
Week 27567891011
Week 2812131415161718
Week 2919202122232425
Week 30262728293031
August 66
MoTuWeThFrSaSu
Week 301
Week 312345678
Week 329101112131415
Week 3316171819202122
Week 3423242526272829
Week 353031
September 66
MoTuWeThFrSaSu
Week 3512345
Week 366789101112
Week 3713141516171819
Week 3820212223242526
Week 3927282930
October 66
MoTuWeThFrSaSu
Week 39123
Week 4045678910
Week 4111121314151617
Week 4218192021222324
Week 4325262728293031
November 66
MoTuWeThFrSaSu
Week 441234567
Week 45891011121314
Week 4615161718192021
Week 4722232425262728
Week 482930
December 66
MoTuWeThFrSaSu
Week 112345
Week 496789101112
Week 5013141516171819
Week 5120212223242526
Week 522728293031

Download Calendar in printable A4 PDF

Find the week number of a date

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 66 starts on January 4, 66 and ends on January 10, 66 (ISO 8601, Monday to Sunday). 66 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.

Frequently Asked Questions (FAQ)

How many weeks does 66 have?

66 has 52 ISO weeks.

When does week 1 of 66 start?

Week 1 of 66 starts on January 4, 66 and ends on January 10, 66 (ISO 8601, Monday to Sunday).

When does the last week of 66 end?

Week 52 of 66 starts on December 27, 66 and ends on January 2, 67 (ISO 8601, Monday to Sunday).

Which years have 53 weeks?

The next years with 53 ISO weeks are 71, 76, 82, 88, 93.

Why do the US and Europe show different week numbers?

Europe follows ISO 8601: weeks start on Monday and week 1 is the week with the first Thursday of the year. In the US, weeks usually start on Sunday and week 1 is the week that contains 1 January, so the two numbers can differ by one.