In SharePoint 2013, the default locale is English (United States). Changing the locale of the site helps display the date and number formats with their respective decimal and group separators. The example below shows changing an existing SharePoint site into UK locale.
$Site = “http://mysite/sites”
$NewLocale = “en-GB”
$Webs = Get-SPWeb -Site $Site
ForEach ($Web In $Webs)
{
If ($Web.locale -ne $NewLocale)
{
$Web.Locale = $NewLocale
$Web.Update()
$Web.Dispose()
}
The above Power shell commands changes locale of all the sites with in a site collection.