It is easy and a single query will do the work.
DECLARE @TimeZone VARCHAR(50)
EXEC xp_regread 'HKEY_LOCAL_MACHINE',
'SYSTEM\CurrentControlSet\Control\TimeZoneInformation',
'TimeZoneKeyName',@TimeZone OUT
SELECT @TimeZone
Result -
(No column name)
1 India Standard Time
If in the query you are not able to find the table then try appending the database and schema name as well like -
Change **xp_regread** to **Master.dbo.xp_regread**