How to set Summer Time (Daylight Savings Time) in Cisco IOS

The Day Light savings time kicked in today in the UK today and it is this part of the year (and when the GMT kicks back in) we do a sanity check on all the Network Devices, Appliances and Servers for time.

It is important to set the time appropriately on the devices as an incorrect time on the devices can cause authentication issues and ofcourse incorrect time stampls on the logs.

You can enable the Day Light Savings time in Cisco IOS. This just takes a couple of commands from the Global Configuration mode.

Set TimeZone

From the Global Configuration mode set the Time Zone you are in.

ciscorouter# conf term

ciscorouter(config)# clock timezone gmt 0

The command above sets the timezone the Cisco Router to GMT (as in UK).

Set Summer Time (Day Light Savings Time)

ciscorouter(config)# clock summer-time BST recurring last Sun Mar 2:00 last Sun Oct 2:00

This command sets the time zone to BST (British Summer Time) between the last day of March at 2am and last Sunday of October 2am after which the timezone reverts back to GMT. This should automatically change the times when the Summer time kicks in.

If the time patterns do not follow a regular pattern as above then you can use one of the following syntax:

clock summer-time <zone> recurring [week day month hh:mm week day month hh:mm [offset]]

clock summer-time zone date date month year hh:mm date month year hh:mm [offset]

clock summer-time zone date month date year hh:mm month date year hh:mm [offset]

where

zone – Name of the time zone (ex: BST) to be displayed when summer time is in effect.
 
week – Week of the month (1 to 5 or last).
 
day – Day of the week (Sunday, Monday, …).
 
date – Date of the month (1 to 31)
 
month – Month (Ex: March)
 
year – Year (1993 to 2035)
 
hh:mm – Time (military format) in hours and minutes
 
offset – Number of minutes to add during summer time (default is 60)

For example,

ciscorouter(config)# clock summer-time date 12 October 2008 2:00 28 April 2009 2:00