Microsoft Daylight Saving Time & Time Zone Blog

This is the blog maintained by staff at Microsoft to provide general information, announcements and provide answers to Frequently Asked Questions (FAQs) related to daylight saving time (DST) and time zone (TZ) changes around the world. * Important Notice

Microsoft Daylight Saving Time & Time Zone Blog

  • December 2013 DST Cumulative Update for Windows Operating Systems

    The December 2013 DST Cumulative Update for Windows Operating Systems has been published on Microsoft Download Center. It contains the following changes: Mid-Atlantic Time: The Mid-Atlantic time zone is deprecated in this update. Morocco...
  • August 2013 DST Cumulative Update for Windows operating systems

    The August 2013 DST Cumulative Update for Windows Operating Systems has been published on Microsoft Download Center. It contains the following changes: Libya Standard Time: New DST starts on the last Friday of March at 2:00 A.M., and ends...
  • Updates available for Paraguay, Turkey and Chile time zones

    This time zone update for Windows Operating Systems has been published on Microsoft Download Center. It contains the following changes: Chile Chile has changed its DST start date to September 7 at 00:00:00 and DST end date to April 27...
  • Armenia cancels DST

    Disclaimer : The information in this document is written in response to an announcement by the government of Armenia about changes in the daylight saving time in Armenia for the year of 2012. The steps provided in this bulletin were created to mitigate...
  • What is an Exchange resource mailbox? How do I find them?

    What is a resource mailbox ? · A resource mailbox is a mailbox that represents conference rooms and company equipment. Resource mailboxes can be included as resources in meeting requests, providing a simple and efficient way to manage the scheduling...
  • Notice: A hotfix is available to update Windows DST support for Egypt, Chile and Morocco

    This hotfix contains three new changes in Windows Daylight Saving Time support : The government of Egypt decided to cancel Daylight Saving Time. This hotfix updates Windows (UTC +2:00) Cairo timezone so it no longer has DST support. ...
  • HOTFIX: Chile Extends 2013 DST

    The government of Chile has extended Daylight Saving Time for 2013 [ Official Decree ]. DST for mainland Chile now ends on April 27, 2013 and starts on September 7, 2013. A hotfix for Windows has been released to address this change. You can find details...
  • December 2012 DST Cumulative Update for Windows operating systems

    The December 2012 DST Cumulative update for Windows operating systems has been published on Microsoft Download Center. It contains the following changes: Bahia Standard Time: Starting in 2012, Bahia Standard Time will no longer have DST. ...
  • Advisory: DST cancellations in Belarus, Ukraine and Armenia

    Ukraine , Belarus , and Armenia have decided to discontinue daylight saving time starting from 2011. These countries are mirroring Russia's changes by staying on "summer time" indefinitely and not falling back to "winter time" on October 30th 2011. Microsoft’s...
  • December 2010 DST Cumulative Update for Windows operating systems

    The December 2010 DST Cumulative Update for Windows operating systems focuses on the following changes : Magadan : o A new timezone has been created for Magadan. The Magadan timezone has support for Daylight Saving Time, with 2011 DST running from...
  • October 2012 DST Cumulative Update for Windows operating systems

    The October 2012 DST Cumulative update for Windows operating systems has been published on Microsoft Download Center. This year’s October Update replaces the normal August Cumulative Update. It contains the following changes: E. Europe Standard...
  • Time Zones not updating on Windows 2003, Windows XP or Windows 2000

    After applying 931836 time zone changes don’t take effect until you manually change the time zone Symptom: We have isolated reports that Windows 2000, XP, and 2003 may find that their Windows clocks do not move forward for DST, even with fixes applied...
  • Update available for Brazil, Fiji and Jordan time zones

    This time zone update for Windows Operating Systems has been published on Microsoft Download Center. It contains the following changes: Jordan: Jordan announced last year that, on December 20, 2013, it would no longer use the daylight saving...
  • Notice: Ukraine and Armenia revert 2011 DST cancellation

    The previous post calls out planned 2011 DST cancellations for Belarus, Ukraine and Armenia [ link ]. We have received reports that Armenia and Ukraine have canceled their proposed changes. According to reports in Rada and Kyivpost , Ukraine will not...
  • August 2011 DST Cumulative Update for Windows operating systems

    The August 2011 DST Cumulative Update for Windows operating systems contains the following changes : NewFoundland : Newfoundland’s DST start and end times have been updated to 2AM from 12:01 AM. The rest of the Newfoundland time zone...
  • Notice: Ramadan Exception for Morocco DST

    As stated in the previous blog post , Microsoft has issued updates for Morocco introducing Daylight Saving Time in 2012 [ KB2698707 ]. Daylight time will be paused during the holy month of Ramadan. Due to the yearly fluctuation of the start and...
  • HOTFIX: Paraguay Shortens 2012-13 DST

    The government of Paraguay has Shortened Daylight Saving Time for 2012-13 [ Official Decree ]. DST for Paraguay now ends on March 23, 2013. A hotfix for Windows has been released to address this change. You can find details of the hotfix and download...
  • Notice : A hotfix is available to update Windows DST support for (UTC +12:00) Fiji, and (UTC -11:00) Samoa

    The government of Fiji revised their 2011 Daylight Saving Time schedule so that it ends the first Sunday in March (March 6 2011), and not the last Sunday in March. More information can be found on http://Fiji.gov.fj Microsoft has implemented a hotfix...
  • Hotfix available for Chile DST change

    The government of Chile has extended Daylight Saving Time for 2012 [ Official Decree ]. DST for mainland Chile now ends on April 28, 2012 and starts on September 1, 2012. A hotfix for Windows has been released to address this change. You can find...
  • Notice : DST schedule updated again for Chile

    Notice : The government of Chile recently decided to extend 2011 Daylight Saving Time again. This impacts the (UTC -4:00) Santiago timezone Instead of ending the first Saturday in April, DST will now end the first Saturday in May. There is no...
  • Notice: a hotfix is available to update Windows DST support for (UTC -4:00) Santiago

    The government of Chile revised their 2011 Daylight Saving Time schedule to defer the ending of DST by three weeks. Instead of ending on Saturday March 12 th , Daylight Saving Time will end on at 24:00:00 Saturday April 2 nd . Clocks should then fall...
  • Notice: a hotfix is available to update Windows DST support for (UTC +2:00) Istanbul

    The Turkish government has decided to change the DST schedule for 2011, pushing back the start-date from March 27 th to March 28 th . The existing timezone (UTC +2:00) Athens, Bucharest, Istanbul is shared with several countries who are not changing their...
  • 2012 DST changes for Morocco

    According to a recent law [ link ] passed by the government of Morocco, Morocco will follow DST each year from 2012. Microsoft is releasing a series of updates for Windows to address this change. You can find details of the updates, including order...
  • December 2011 DST Cumulative Update for Windows operating systems

    The December 2011 DST Cumulative update for Windows operating systems has been published on Microsoft Download Center. It contains the following changes: Kaliningrad Standard Time: As previously announced in KB2625508 , Belarus has decided to discontinue...
  • Missing entries for specific time zones in the registry

    Q: My machines are missing entries for specific time zones from the registry. What do I do? A: When a machine is in the state of missing a time zone key the installation of 931836 will result in the missing key structure being restored, but not the...