In Windows PowerShell type these two commands to establish daylight saving time status of system clock. It wll return either true or false.

$a = Get-Date
$a.IsDaylightSavingTime()

Tested in Win 7 presumably works on 8.1

Of course the linux equivalent of get-date is more versatile;

$ TZ="Africa/Timbuktu" date
Tue Apr 8 00:50:53 GMT 2014