Back in 2006, Google allowed their AdWords advertisers to change their time zones once because of a billing structure update. When that was done, they said no more changes allowed to that setting. Except there were exceptions to the rule and there still are.
A Google AdWords Help thread has one advertiser asking how he can go about changing the time zone setting in their AdWords account. It is a fairly wanted feature that still is not encouraged by Google - but why?
Google says that this is tied to your billing and changing it impacts your reporting and billing. Google writes:
Your reports, statistics, and billing are all affected by the time zone you select. For example, settings such as your daily budget run on a 24-hour schedule. We recommend you choose your local time zone so your budget cycle ends when your day ends.
Google then goes on to say that they will change it once in the life of the AdWords account:
In the event you set your account time zone in error, account time zones may be changed up to one time over the life of an account.
Clearly Google doesn't want you changing this setting.
But if you need to, you can request a change by clicking here.
Forum discussion at Google AdWords Help.
Image credit: BigStockPhoto for time zones image