Manually Updating Microsoft Windows For Daylight Saving Changes

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Method 1: Use the Tzedit.exe utility to manually modify the time zone

The tzedit.exe utility, which is part of the Windows Resource Kit, can be used to set or change the start and the end dates for daylight saving for one or more time zones. TzEdit can be found here

 For more information about Windows Resource kits, visit the Microsoft Windows Deployment and Resource Kits web site. The following example shows how to set start and end dates for New Zealand’s daylight savings.

Note that the end time for daylight saving is expressed in daylight saving time, not standard time.

1.

Click Start, point to Programs, point to Windows Resource Kit, and then click Tools.

2.

Double-click Alphabetical list of Tools, and then click Time Zone Editor.

3.

Scroll through the list of time zones to locate the (GMT+12:00) Auckland, Wellington entry. If the entry is not found: Click New, and then type (GMT+12:00) Auckland, Wellington in the Time Zone Name box and follow the instructions below. If the entry is found: Click on the entry, click Edit, then adjust the settings according to the instructions below

4.

In the Abbreviation box, type New Zealand Standard Time.

5.

In the Offset from GMT box, type +12:00.

6.

Click to select the Automatically set daylight-saving time check box.

7.

Follow these steps:

a.

In the first Start Day box, click Last.

b.

In the second Start Day box, click Sunday.

c.

In the third Start Day box, click September.

d.

In the fourth Start Day box, click 2:00 AM.

e.

In the first Last Day box, click First.

f.

In the second Last Day box, click Sunday.

g.

In the third Last Day box, click April.

h.

In the fourth Last Day box, click 3:00 AM.

i.

In the Abbreviation box, type New Zealand Daylight Time.

j.

In the Daylight Bias box, click +1:00 to set the clock forward 1 hour. By default, Daylight Bias is set to +1:00.

8.

Click OK, and then quit Windows Time Zone Editor.

9.

Click Start, point to Settings, and then click Control Panel.

10.

Double-click Date/Time, and then click the Time Zone tab.

11.

Click (GMT+12:00) Auckland, Wellington and then click OK.

12.

Click to select the Automatically adjust clock for daylight saving changes check box, click Apply, and then click OK.

13.

To test that the new time zone setting will adjust for daylight savings as expected, change the time and date on your computer to several minutes before the time that you have set for the daylight-saving time changes. Verify that the daylight-saving time changes are correct when the change occurs.

Method 2: Update the Windows Registry Directly

Time zone entries in the Windows registry can be updated directly using a script file. This method is useful when more than one system needs to be updated, for example in a commercial environment.

1. Create a file named TimeZones.reg containing the update script (see below for examples).

2. Double-click the Timezones.reg file.

3. Click Yes when you are prompted to add information to the registry.

4. Click OK when you receive the message that the information was successfully entered in the registry.

5. Click Start, point to Settings, and then click Control Panel.

6. Double-click Date/Time, and then click the Time Zone tab.

7. Click on the time zone you have just updated, and then click OK.

8. Click to select the Automatically adjust clock for daylight saving changes check box, click Apply, and then click OK.

Before updating your registry please back up any registry keys before proceeding.

Sample Script – New Zealand 2007 Daylight Saving ChangesWindows Registry Editor Version 5.00[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Time Zones\New Zealand Standard Time]"Display"="(GMT+12:00) Auckland, Wellington""Dlt"="New Zealand Daylight Time""Std"="New Zealand Standard Time""MapID"="78,79""Index"=dword:00000122"TZI"=hex:30,fd,ff,ff,00,00,00,00,c4,ff,ff,ff,00,00,04,00,00,00,01,00,03,00,00,00,00,00,00,00,00,00,09,00,00,00,05,00,02,00,00,00,00,00,00,00[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Time Zones\New Zealand Standard Time\Dynamic DST]"FirstEntry"=dword:000007d6"LastEntry"=dword:000007d8"2006"=hex:30,fd,ff,ff,00,00,00,00,c4,ff,ff,ff,00,00,03,00,00,00,03,00,03,00,00,00,00,00,00,00,00,00,0a,00,00,00,01,00,02,00,00,00,00,00,00,00"2007"=hex:30,fd,ff,ff,00,00,00,00,c4,ff,ff,ff,00,00,03,00,00,00,03,00,03,00,00,00,00,00,00,00,00,00,09,00,00,00,05,00,02,00,00,00,00,00,00,00"2008"=hex:30,fd,ff,ff,00,00,00,00,c4,ff,ff,ff,00,00,04,00,00,00,01,00,03,00,00,00,00,00,00,00,00,00,09,00,00,00,05,00,02,00,00,00,00,00,00,00

 

Testing the update:

1.

Change the date/clock to September 30, 2007, 1:59am and verify that the clock advances one hour (instead of moving to 2am it moves to 3am). This is the new (2007) DST start date.

2.

Change the date/clock to October 7, 2007 at 1:59am and verify that the clock does not adjust for DST (Simply moves to 2am). This is the 2007 DST start date.

3.

Change the date/clock to March 16, 2008 at 1:59am and verify that the clock does not adjust for DST (Simply moves to 2am). This is the 2008 DST end date.

4.

Change the date/clock to April 6, 2008 at 2:59am and verify that the clock goes back one hour to 2:00am (instead of 3am). This is the new (2008) DST end date.