Microsoft Windows August 2011 Updates to Daylight Saving Time and Time Zones, including Russia

Microsoft Office Clip ArtCheck out Microsoft KB article 2570791 for the August 2011 cumulative time zone update for Windows operating systems, just posted this week. (This update supersedes and replaces update 2443685, which was released in December 2010. This update also includes additional time zone changes released as hotfixes after update 2443685 was published.)

The August 2011 DST cumulative update contains revisions for the coming changes in Russia as noted in my previous post, with updates to the UTC offsets and removes DST for the affected Russian time zones as follows:


Time Zone



Russian Standard Time (UTC +3:00) Moscow, St Petersburg, Volgograd (UTC +4:00) Moscow, St Petersburg, Volgograd
Ekaterinburg Standard Time (UTC +5:00) Ekaterinburg (UTC +6:00) Ekaterinburg
N. Central Asia Standard Time (UTC +6:00) Novosibirsk (UTC +7:00) Novosibirsk
North Asia Standard Time (UTC +7:00) Krasnoyarsk (UTC +8:00) Krasnoyarsk
North Asia East Standard Time (UTC +8:00) Irkutsk (UTC +9:00) Irkutsk
Yakutsk Standard Time (UTC +9:00) Yakutsk (UTC +10:00) Yakutsk
Vladivostok Standard Time (UTC +10:00) Vladivostok (UTC +11:00) Vladivostok
Magadan Standard Time (UTC +11:00) Magadan (UTC +12:00) Magadan

A new Windows time zone was created, Kaliningrad Standard Time [Display Name “(UTC+3:00) Kaliningrad”]:
with the display name “(UTC+3:00) Kaliningrad.” This time zone does not observe daylight saving time.

It also includes revisions to the following time zones:

The following changes were made since the previous Windows cumulative time zone update:

  • Turkey Standard Time:
    A new Windows time zone was created: Turkey Standard Time. The display name is “(UTC+2:00) Istanbul.” The government of Turkey has decided to change the 2011 DST schedule. It will start on Monday March 28 instead of Sunday March 27.
    “Istanbul” was removed from the display name of the “(UTC+2:00) Athens, Bucharest, Istanbul” time zone.
  • Egypt Standard Time [Display Name “(UTC+2:00) Cairo”]:
    The government of Egypt has canceled daylight saving time.
  • Pacific SA Standard Time [Display Name “(UTC-4:00) Santiago”]:
    Sets the 2011 DST start date to occur in August and the end date to occur in May. 
  • Morocco Standard Time [Display Name “(UTC) Casablanca”]:
    Sets the 2011 DST end date to occur in July.
  • Fiji Standard Time [Display Name “(UTC+12:00) Fiji”]:
    Sets the 2011 DST end date to occur on the first Sunday in March.
  • Samoa Standard Time [Display Name “(UTC-11:00) Samoa”]:
    Sets the 2011 DST end time to occur one hour later.

Also note: The DST start time and end time for Newfoundland Standard Time [Display Name “(UTC-3:30) Newfoundland”] has been updated  from 12:01 A.M. to 2:00 A.M.

For more information about how daylight saving time changes may affect other Microsoft products, click the following article number to view the article in the Microsoft Knowledge Base: 914387  ( How to configure daylight saving time for Microsoft Windows operating systems.

So what should you do to make sure that your computers are ready for the change?

Most applications and services reference the underlying Windows operating system for their date and time related rules, with some exceptions. We outline the various software updates to select Microsoft products (including various releases of the Microsoft Windows operating systems, Microsoft Office and other applications) on the Microsoft Daylight Saving Time Help and Support Center. There, we have information and links to updates for various products in mainstream and extended support affected by this change, as well as other various changes to DST offsets and time zones around the world.

If you use Microsoft Update on your PC at home, chances are you’re already covered. The latest update – the August 2011 Cumulative Time Zone Update for Windows – may already be installed on your PC if you have turned on Automatic Update in Windows. This ensures you’ll get the latest security and other important updates from Microsoft automatically. This latest update includes the changes for Russia as well as other worldwide changes (including Turkey, Egypt, Morocco, Fiji, Samoa and Newfoundland). If you’re not sure if the update has been applied, visit the Microsoft Update site for more information.

If someone manages your network at work, it’s likely the needed updates are schedule to be deployed to your computers and devices, if they haven’t been installed already.

For IT professionals managing PCs, servers and Microsoft software installations, please visit for more details. Also, visit the support websites of any other software companies to see if you need to apply any updates. It’s not just Microsoft software that may require updates. Additionally, for the change in Russia, we provide specific details and guidance in country at

While Microsoft’s Services infrastructure will be updated to reflect DST changes, it’s important that your computers — both clients and servers that interact with these services — should have the latest Windows cumulative updates for DST and time zone changes applied in order to ensure data integrity.

A holiday nod of thanks to the good folks across our company working on our effort to help manage time (particularly in daylight saving time and time zone changes) — documented and followed at and over at the blog at — and to the folks coordinating the efforts on our daylight saving time and time zone updates and releases for current products across the various product groups at Microsoft.  As noted, this is a tough job, to say the least.

Tags: Windows, Microsoft, Daylight Saving Time, Daylight Savings Time, RSS, DST, Russia; 17,400,000; 23,100,000 (up ~5M results from the last time I Binged it)

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One reply on “Microsoft Windows August 2011 Updates to Daylight Saving Time and Time Zones, including Russia”

Some days ago, I installed new Windows updates, and found out that all Russians timezones have changed.

This new timezones failed to convert times before 26.03.2011 2:00 to UTC correctly.

As I see, in all new Russians timezones BaseUtcOffset was increased by 1. And thay all has only one adjustment rule, which ends in 31.12.2010, and marks daylight saving time from end or march to end of october.

It would be correct for old value of BaseUtcOffset. But with increased BaseUtcOffset it forces TimeZoneInfo to add an wrong extra hour when convert time from UTC, and sub wrong extra hour when convert time to UTC.

To fix this error, it needs to keep old BaseUtcOffset in all Russian Time Zones, and add new adjustment rule, which strarts from 27.03.2011, ends, for example, in 31.12.9999 and marks daylight saving time for all year.

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