Week numbers 509

509 has 52 ISO weeks. Week 1: Dec 31, 508 – Jan 6, 509 · Week 52: Dec 23 – 29

509 at a glance

Weeks in 50952
Week 1December 31, 508 – January 6, 509
Week 52December 23, 509 – December 29, 509
Days in 509365
Leap yearNo

All Weeks in 509

Week From To Month
Week 1 in 509 December 31, 508 January 6, 509 December / January
Week 2 in 509 January 7, 509 January 13, 509 January
Week 3 in 509 January 14, 509 January 20, 509 January
Week 4 in 509 January 21, 509 January 27, 509 January
Week 5 in 509 January 28, 509 February 3, 509 January / February
Week 6 in 509 February 4, 509 February 10, 509 February
Week 7 in 509 February 11, 509 February 17, 509 February
Week 8 in 509 February 18, 509 February 24, 509 February
Week 9 in 509 February 25, 509 March 3, 509 February / March
Week 10 in 509 March 4, 509 March 10, 509 March
Week 11 in 509 March 11, 509 March 17, 509 March
Week 12 in 509 March 18, 509 March 24, 509 March
Week 13 in 509 March 25, 509 March 31, 509 March
Week 14 in 509 April 1, 509 April 7, 509 April
Week 15 in 509 April 8, 509 April 14, 509 April
Week 16 in 509 April 15, 509 April 21, 509 April
Week 17 in 509 April 22, 509 April 28, 509 April
Week 18 in 509 April 29, 509 May 5, 509 April / May
Week 19 in 509 May 6, 509 May 12, 509 May
Week 20 in 509 May 13, 509 May 19, 509 May
Week 21 in 509 May 20, 509 May 26, 509 May
Week 22 in 509 May 27, 509 June 2, 509 May / June
Week 23 in 509 June 3, 509 June 9, 509 June
Week 24 in 509 June 10, 509 June 16, 509 June
Week 25 in 509 June 17, 509 June 23, 509 June
Week 26 in 509 June 24, 509 June 30, 509 June
Week 27 in 509 July 1, 509 July 7, 509 July
Week 28 in 509 July 8, 509 July 14, 509 July
Week 29 in 509 July 15, 509 July 21, 509 July
Week 30 in 509 July 22, 509 July 28, 509 July
Week 31 in 509 July 29, 509 August 4, 509 July / August
Week 32 in 509 August 5, 509 August 11, 509 August
Week 33 in 509 August 12, 509 August 18, 509 August
Week 34 in 509 August 19, 509 August 25, 509 August
Week 35 in 509 August 26, 509 September 1, 509 August / September
Week 36 in 509 September 2, 509 September 8, 509 September
Week 37 in 509 September 9, 509 September 15, 509 September
Week 38 in 509 September 16, 509 September 22, 509 September
Week 39 in 509 September 23, 509 September 29, 509 September
Week 40 in 509 September 30, 509 October 6, 509 September / October
Week 41 in 509 October 7, 509 October 13, 509 October
Week 42 in 509 October 14, 509 October 20, 509 October
Week 43 in 509 October 21, 509 October 27, 509 October
Week 44 in 509 October 28, 509 November 3, 509 October / November
Week 45 in 509 November 4, 509 November 10, 509 November
Week 46 in 509 November 11, 509 November 17, 509 November
Week 47 in 509 November 18, 509 November 24, 509 November
Week 48 in 509 November 25, 509 December 1, 509 November / December
Week 49 in 509 December 2, 509 December 8, 509 December
Week 50 in 509 December 9, 509 December 15, 509 December
Week 51 in 509 December 16, 509 December 22, 509 December
Week 52 in 509 December 23, 509 December 29, 509 December

Calendars 509

January 509
MoTuWeThFrSaSu
Week 1123456
Week 278910111213
Week 314151617181920
Week 421222324252627
Week 528293031
February 509
MoTuWeThFrSaSu
Week 5123
Week 645678910
Week 711121314151617
Week 818192021222324
Week 925262728
March 509
MoTuWeThFrSaSu
Week 9123
Week 1045678910
Week 1111121314151617
Week 1218192021222324
Week 1325262728293031
April 509
MoTuWeThFrSaSu
Week 141234567
Week 15891011121314
Week 1615161718192021
Week 1722232425262728
Week 182930
May 509
MoTuWeThFrSaSu
Week 1812345
Week 196789101112
Week 2013141516171819
Week 2120212223242526
Week 222728293031
June 509
MoTuWeThFrSaSu
Week 2212
Week 233456789
Week 2410111213141516
Week 2517181920212223
Week 2624252627282930
July 509
MoTuWeThFrSaSu
Week 271234567
Week 28891011121314
Week 2915161718192021
Week 3022232425262728
Week 31293031
August 509
MoTuWeThFrSaSu
Week 311234
Week 32567891011
Week 3312131415161718
Week 3419202122232425
Week 35262728293031
September 509
MoTuWeThFrSaSu
Week 351
Week 362345678
Week 379101112131415
Week 3816171819202122
Week 3923242526272829
Week 4030
October 509
MoTuWeThFrSaSu
Week 40123456
Week 4178910111213
Week 4214151617181920
Week 4321222324252627
Week 4428293031
November 509
MoTuWeThFrSaSu
Week 44123
Week 4545678910
Week 4611121314151617
Week 4718192021222324
Week 48252627282930
December 509
MoTuWeThFrSaSu
Week 21
Week 492345678
Week 509101112131415
Week 5116171819202122
Week 5223242526272829
Week 13031

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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 509 starts on December 31, 508 and ends on January 6, 509 (ISO 8601, Monday to Sunday). 509 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 509 have?

509 has 52 ISO weeks.

When does week 1 of 509 start?

Week 1 of 509 starts on December 31, 508 and ends on January 6, 509 (ISO 8601, Monday to Sunday).

When does the last week of 509 end?

Week 52 of 509 starts on December 23, 509 and ends on December 29, 509 (ISO 8601, Monday to Sunday).

Which years have 53 weeks?

The next years with 53 ISO weeks are 511, 516, 522, 528, 533.

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.