Dates that cause trouble with computers or are significant to computers.

Issues related to dates in the far future will be collected somewhere else.

Also see Troublesome Times.

January 1, 4713 BCPermalink

Beginning of the Julian Day system.

NOTE: The “Julian” in “Julian Day” is unrelated to the “Julian” in “Julian Calendar”!

January 1, 45 BCPermalink

Julian Calendar takes effect.

NOTE: The “Julian” in “Julian Day” is unrelated to the “Julian” in “Julian Calendar”!

Year 24Permalink

Year 2024 confused with year 24.

March 1, 4 ADPermalink

Earliest date that Julian calendar and Gregorian calendar calculations are historically accurate.

January 1, 100 ADPermalink

LotusScript counts days from January 1, 100 AD.

October 4, 1582Permalink

Gregorian Calendar takes effect.

Pope Gregory XIII decreed Thursday, October 4, 1582, was followed by Friday, October 15.

October 5, 1582 to October 14, 1582Permalink

In some countries, October 5, 1582 to October 14, 1582 were skipped when switching from Julian calendar to Gregorian Calendar.

Java GregorianCalendar class skips these dates.

October 15, 1582Permalink

Gregorian Calendar was first adopted by the bulk of Europe.

Base for Versions 1 and 6 UUIDs.

January 1, 1601Permalink

FILETIME structure in Windows starts counting from January 1, 1601.

September, 1752Permalink

The British authorities declared that September 2, 1752, would be followed by September 14, 1752 when switching from Julian calendar to Gregorian Calendar.

September 3, 1752 to September 13, 1752 were skipped when switching from Julian calendar to Gregorian calendar.

January 1, 1753Permalink

SQL Server datetime starts counting from January 1, 1753.

September 22, 1792Permalink

Start of French Revolutionary calendar.

November 17, 1858Permalink

November 17, 1858 is the base of the Modified Julian Day system.

Julian Day 2,400,000 is November 17, 1858.

The Modified Julian Day uses the following formula:

MJD = JD - 2,400,000.5

1885Permalink

time.minWall default Go is 1885.

December 30, 1899Permalink

January 0 1900 (December 31, 1899)Permalink

Excel stores dates and times as a number representing the number of days since 1900-Jan-0.

February 29, 1900Permalink

This is because Excel behaves as if the date 1900-Feb-29 existed. It did not.

December 13, 1901Permalink

The next second this counter can represent is 20:45:52 UTC on December 13, 1901.

December 31 1903 / January 0, 1904Permalink

…but Excel can also treat the date portion of a serial date as the number of days since 1904-Jan-0.

January 1, 1904Permalink

old Macintosh epoch.

1912Permalink

Start of Taiwan calendar.

December 31, 1927Permalink

January 1, 1970 (December 31, 1969)Permalink

23andMe Epoch Error

January 1, 1971Permalink

January 4, 1975Permalink

On 4 January 1975, the 12-bit field that had been used for dates in the DECsystem-10 operating systems overflowed.

April 4, 1975Permalink

…but the developer who fixed the bug decided to be a bit clever: He chose April 4, 1975, the date of Microsoft’s founding.

1978Permalink

January 6, 1980Permalink

GPS epoch

September 18, 1989Permalink

2^16 days since January 1 1900

September 18, 1993Permalink

firstDIVUWithA8C0Overflows = 2831155200

January 1 1904 (old Macintosh epoch) + firstDIVUWithA8C0Overflows = September 18 1993

October 29, 1995Permalink

November 2, 1997Permalink

Around April First of this year reports started circulating in the Apollo Usenet newsgroup of a “date bug” in Domain/OS that would render all Apollo workstations useless after November 2, 1997.

In[178]:= DateList[{1980, 1, 1}];
DatePlus[%, Quantity[ (4*2^47)/10^6 , "Second"]]

Out[179]= {1997, 11, 2, 14, 59, 13.4213}

1999Permalink

2000Permalink

Y2K

January 1, 2001Permalink

September 9, 2001Permalink

January 2, 2006Permalink

May 13, 2006Permalink

It sound like that could equate to “Sat May 13 02:27:28 BST 2006”, or 1147483648 seconds since epoch, which makes it exactly 1,000,000,000 seconds until expiry of 32 bit time. Coincidence? Seems too strange as to a computer that is not a nice round number.

March 28, 2007Permalink

firstDIVUWithA8C0Overflows = 2831155200

January 1 1904 (old Macintosh epoch) + firstDIVUWithA8C0Overflows = September 18 1993

September 18 1993 + 5000 days = May 28 2007

December 2, 2007Permalink

Sunday December 2 is beginning of GPS week 432

592 weeks before next GPS week rollover

June 14, 2008Permalink

…it means that 2008-06-14 23:29:20 UTC is, in a strange sense, “HTTP time”. If you see either that number or that date (with possible adjustments for your local time zone) showing up in your life inexplicably, this might just be why.

December 31, 2008Permalink

The bug would be triggered on the last day of any leap year

2010Permalink

November 2010Permalink

December 12, 2010Permalink

Sunday December 12 is beginning of GPS week 590

434 weeks before next GPS week rollover

Rollover date for various Furuno GPS equipment.

2011Permalink

January 1, 2011Permalink

June 30, 2012Permalink

June 30, 2012 leap second

January 2013Permalink

March 10, 2013Permalink

Daylight Saving Time begins on Sunday March 10, 2013

August 11, 2013Permalink

2^32 deci-seconds from January 1, 2000

Sunday August 11 is beginning of GPS week 729

ALSO 295 weeks before next GPS week rollover

Rollover date for various Furuno GPS equipment.

End of 2014Permalink

ISO week vs. Gregorian week

September 5, 2015Permalink

If system used by Apollo workstation was unsigned

In[3]:= DateList[{1980, 1, 1}];
DatePlus[%, Quantity[(4*2^48)/10^6, "Second"]]

Out[4]= {2015, 9, 5, 5, 58, 26.8426}

January 1, 2016Permalink

August 16, 2017Permalink

1024 weeks since January 1, 1998

September 17, 2017Permalink

Sunday September 17 is beginning of GPS week 943

Rollover date for various Furuno GPS equipment.

December 2017Permalink

“Month 13 is out of bounds”

August 19, 2018Permalink

Sunday August 19 is beginning of GPS week 991

Rollover date for various Furuno GPS equipment.

September 16, 2018Permalink

Sunday September 16 is beginning of GPS week 995

Rollover date for various Furuno GPS equipment.

October 6, 2018Permalink

October 21, 2018Permalink

GPS Week Number reached 1,000

March 17, 2019Permalink

Sunday March 17 is beginning of GPS week 1021

3 weeks before next GPS week rollover

Rollover date for various Furuno GPS equipment.

April 6, 2019Permalink

Last day before GPS rollover

April 7, 2019Permalink

Sunday April 7 is beginning of GPS week 0

April 30, 2019Permalink

November 3, 2019Permalink

Sunday November 3 is beginning of GPS week 30

End of 2019Permalink

ISO week vs. Gregorian week

2020Permalink

Y2K20

February 29, 2020Permalink

2020 leap day bugs

December 20, 2020Permalink

Sunday December 20 is beginning of GPS week 89

Rollover date for various Furuno GPS equipment.

2021Permalink

June 20, 2021Permalink

Sunday June 20 is beginning of GPS week 115

Rollover date for various Furuno GPS equipment.

October 23, 2021Permalink

January 2, 2022Permalink

Sunday January 2 is beginning of GPS week 143

Rollover date for various Furuno GPS equipment.

May 15 2022Permalink

Sun May 15 is beginning of GPS week 162

September 18 2022Permalink

Sun September 18 is beginning of GPS week 180

Rollover date for various Furuno GPS equipment.

March ?, 2023Permalink

Raystar 125

2024Permalink

February 29, 2024Permalink

Leap day

Payment card readers at petrol pumps in New Zealand were unable to handle the leap year and were unable to properly dispense gasoline.[41] https://www.reuters.com/world/asia-pacific/leap-year-glitch-shuts-some-new-zealand-fuel-pumps-2024-02-29/

Video games EA Sports WRC and Theatrhythm Final Bar Line also suffered issues related to the leap year, with the former crashing when trying to load the game and the latter claiming that the save data was corrupted. Both games had to be set to the following day of March 1, 2024 to properly work.[42][43][44]

https://kotaku.com/final-fantasy-theatrhythm-broken-wrc-leap-day-bug-ps4-1851298039

https://www.ign.com/articles/theatrhythm-final-fantasy-on-nintendo-switch-doesnt-work-today-feb-29-seemingly-because-its-a-leap-year

https://www.ign.com/articles/ea-sports-wrc-crashing-on-start-up-today-feb-29-because-2024s-a-leap-year

March 24, 2024Permalink

Sunday March 24 is beginning of GPS week 259

Rollover date for various Furuno GPS equipment.

December 13, 2024Permalink

In December 2024, a 30 year old bug was found in all versions of HCL Notes. When the server is started on or after December 13 2024, an overflow will prevent the mail router to load its configuration, and so no mail is delivered. Patches were released on the next day for all supported versions.

The date/time issue made the TimeDateDifference() internal call return incorrect results under certain conditions, and dates back to the core Notes program in 1986.

December 31, 2024Permalink

Last day in leap year

2025Permalink

In Japan, some older computer systems using the Japanese calendar that have not been updated still count years according to the Shōwa era. The year 2025 corresponds in those systems to Shōwa 100, which can cause problems if the software assumes two digits for the year.[46]

In Spain, all Talgo AVRIL class trains stopped operating on January 1, 2025 due to a date handling bug in the battery charging module, causing delays and cancellations as passengers were relocated in other rolling stock.[47][48] A bugfix was deployed by the next day, recovering regular service.[49]

2028Permalink

2032Permalink

February 7, 2036Permalink

January 1 1900 + 2^32 Second == February 7 2036

January 19, 2038Permalink

With 32 bit signed integers, Unix time will overflow on: 03:14:08 UTC January 19, 2038

November 20, 2038Permalink

GPS Week rollover

February 6, 2040Permalink

old macintosh calendar expires

September 18, 2042Permalink

2043Permalink

Microsoft Exchange update format

changing to unsigned long

January 19, 2048Permalink

2069Permalink

December 30, 2078Permalink

2079Permalink

2080Permalink

2100Permalink

2106Permalink

unsigned 32-bit count of seconds (also) since 1970

With 2^5 = 32 bit unsigned integers, Unix time will overflow on: 06:28:16 UTC February 07, 2106

2108Permalink

2137Permalink

GPS 13-bit week rollover

November 4, 2153Permalink

March 16, 2157Permalink

// Seconds field overflowed the 33 bits available when // storing a monotonic time. This will be true after // March 16, 2157.

2232Permalink

2262Permalink

April 4, 2262Permalink

2262-04-11 23:47:16 UTC is when a system with a signed 64 bit number to store Unix time shifted left with nanoseconds added to it runs out of time.

2286Permalink

July 21, 2554Permalink

2554-07-21 23:34:33 UTC is when the same scheme but with an unsigned 64 bit number runs out of time.

~3400Permalink

Since a UUID is a fixed size and contains a time field, it is possible for values to rollover (around A.D. 3400, depending on the specific algorithm used).

3603Permalink

The rollover time as defined by ITU-T Rec. X.667 is 3603 AD.

4000Permalink

4147Permalink

4501Permalink

5623Permalink

However some software, such as the libuuid library, treats the timestamp as unsigned, putting the rollover time in 5623 AD.