Week numbers 2009

2009 has 53 ISO weeks, because 1 January 2009 falls on a Thursday. Week 1 of 2009 starts on December 29, 2008 and ends on January 4, 2009 (ISO 8601, Monday to Sunday).

2009 at a glance

Weeks in 200953
Week 1December 29, 2008 – January 4, 2009
Week 53December 28, 2009 – January 3, 2010
Days in 2009365
Leap yearNo

All Weeks in 2009

Week From To Month
Week 1 in 2009 December 29, 2008 January 4, 2009 December / January
Week 2 in 2009 January 5, 2009 January 11, 2009 January
Week 3 in 2009 January 12, 2009 January 18, 2009 January
Week 4 in 2009 January 19, 2009 January 25, 2009 January
Week 5 in 2009 January 26, 2009 February 1, 2009 January / February
Week 6 in 2009 February 2, 2009 February 8, 2009 February
Week 7 in 2009 February 9, 2009 February 15, 2009 February
Week 8 in 2009 February 16, 2009 February 22, 2009 February
Week 9 in 2009 February 23, 2009 March 1, 2009 February / March
Week 10 in 2009 March 2, 2009 March 8, 2009 March
Week 11 in 2009 March 9, 2009 March 15, 2009 March
Week 12 in 2009 March 16, 2009 March 22, 2009 March
Week 13 in 2009 March 23, 2009 March 29, 2009 March
Week 14 in 2009 March 30, 2009 April 5, 2009 March / April
Week 15 in 2009 April 6, 2009 April 12, 2009 April
Week 16 in 2009 April 13, 2009 April 19, 2009 April
Week 17 in 2009 April 20, 2009 April 26, 2009 April
Week 18 in 2009 April 27, 2009 May 3, 2009 April / May
Week 19 in 2009 May 4, 2009 May 10, 2009 May
Week 20 in 2009 May 11, 2009 May 17, 2009 May
Week 21 in 2009 May 18, 2009 May 24, 2009 May
Week 22 in 2009 May 25, 2009 May 31, 2009 May
Week 23 in 2009 June 1, 2009 June 7, 2009 June
Week 24 in 2009 June 8, 2009 June 14, 2009 June
Week 25 in 2009 June 15, 2009 June 21, 2009 June
Week 26 in 2009 June 22, 2009 June 28, 2009 June
Week 27 in 2009 June 29, 2009 July 5, 2009 June / July
Week 28 in 2009 July 6, 2009 July 12, 2009 July
Week 29 in 2009 July 13, 2009 July 19, 2009 July
Week 30 in 2009 July 20, 2009 July 26, 2009 July
Week 31 in 2009 July 27, 2009 August 2, 2009 July / August
Week 32 in 2009 August 3, 2009 August 9, 2009 August
Week 33 in 2009 August 10, 2009 August 16, 2009 August
Week 34 in 2009 August 17, 2009 August 23, 2009 August
Week 35 in 2009 August 24, 2009 August 30, 2009 August
Week 36 in 2009 August 31, 2009 September 6, 2009 August / September
Week 37 in 2009 September 7, 2009 September 13, 2009 September
Week 38 in 2009 September 14, 2009 September 20, 2009 September
Week 39 in 2009 September 21, 2009 September 27, 2009 September
Week 40 in 2009 September 28, 2009 October 4, 2009 September / October
Week 41 in 2009 October 5, 2009 October 11, 2009 October
Week 42 in 2009 October 12, 2009 October 18, 2009 October
Week 43 in 2009 October 19, 2009 October 25, 2009 October
Week 44 in 2009 October 26, 2009 November 1, 2009 October / November
Week 45 in 2009 November 2, 2009 November 8, 2009 November
Week 46 in 2009 November 9, 2009 November 15, 2009 November
Week 47 in 2009 November 16, 2009 November 22, 2009 November
Week 48 in 2009 November 23, 2009 November 29, 2009 November
Week 49 in 2009 November 30, 2009 December 6, 2009 November / December
Week 50 in 2009 December 7, 2009 December 13, 2009 December
Week 51 in 2009 December 14, 2009 December 20, 2009 December
Week 52 in 2009 December 21, 2009 December 27, 2009 December
Week 53 in 2009 December 28, 2009 January 3, 2010 December / January

Calendars 2009

January 2009
MoTuWeThFrSaSu
Week 11234
Week 2567891011
Week 312131415161718
Week 419202122232425
Week 5262728293031
February 2009
MoTuWeThFrSaSu
Week 51
Week 62345678
Week 79101112131415
Week 816171819202122
Week 9232425262728
March 2009
MoTuWeThFrSaSu
Week 91
Week 102345678
Week 119101112131415
Week 1216171819202122
Week 1323242526272829
Week 143031
April 2009
MoTuWeThFrSaSu
Week 1412345
Week 156789101112
Week 1613141516171819
Week 1720212223242526
Week 1827282930
May 2009
MoTuWeThFrSaSu
Week 18123
Week 1945678910
Week 2011121314151617
Week 2118192021222324
Week 2225262728293031
June 2009
MoTuWeThFrSaSu
Week 231234567
Week 24891011121314
Week 2515161718192021
Week 2622232425262728
Week 272930
July 2009
MoTuWeThFrSaSu
Week 2712345
Week 286789101112
Week 2913141516171819
Week 3020212223242526
Week 312728293031
August 2009
MoTuWeThFrSaSu
Week 3112
Week 323456789
Week 3310111213141516
Week 3417181920212223
Week 3524252627282930
Week 3631
September 2009
MoTuWeThFrSaSu
Week 36123456
Week 3778910111213
Week 3814151617181920
Week 3921222324252627
Week 40282930
October 2009
MoTuWeThFrSaSu
Week 401234
Week 41567891011
Week 4212131415161718
Week 4319202122232425
Week 44262728293031
November 2009
MoTuWeThFrSaSu
Week 441
Week 452345678
Week 469101112131415
Week 4716171819202122
Week 4823242526272829
Week 4930
December 2009
MoTuWeThFrSaSu
Week 2123456
Week 5078910111213
Week 5114151617181920
Week 5221222324252627
Week 5328293031

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 2009 starts on December 29, 2008 and ends on January 4, 2009 (ISO 8601, Monday to Sunday). 2009 has 53 ISO weeks, because 1 January 2009 falls on a Thursday.

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 2009 have?

2009 has 53 ISO weeks, because 1 January 2009 falls on a Thursday.

When does week 1 of 2009 start?

Week 1 of 2009 starts on December 29, 2008 and ends on January 4, 2009 (ISO 8601, Monday to Sunday).

When does the last week of 2009 end?

Week 53 of 2009 starts on December 28, 2009 and ends on January 3, 2010 (ISO 8601, Monday to Sunday).

Which years have 53 weeks?

The next years with 53 ISO weeks are 2009, 2015, 2020, 2026, 2032.

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.