Determine my time zone offset using VBScript?

Question

How can I determine my time zone offset using VBScript?

The Windows OS provides the TZ environment variable. For Eastern Standard Time (New York), its value is EST5EDT. However, I am looking for the signed integer offset from UTC. (This is -5 for Eastern Standard Time.)

Answer 1

Here is a revised function that appears to account for Daylight Saving Time. (Inspired by this SO question.)

Function GetTimeZoneOffset()
    Const sComputer = "."

    Dim oWmiService : Set oWmiService = _
        GetObject("winmgmts:{impersonationLevel=impersonate}!\\" _
                  & sComputer & "\root\cimv2")

    Set cItems = oWmiService.ExecQuery("SELECT * FROM Win32_ComputerSystem")

    For Each oItem In cItems
        GetTimeZoneOffset = oItem.CurrentTimeZone / 60
        Exit For
    Next
End Function

---

[Original function that does NOT account for Daylight Saving Time.]

Here is my answer to my question (original source).

For Eastern Standard Time (New York), this VBScript function will return -5:

Function GetTimeZoneOffset()
    Const sComputer = "."

    Dim oWmiService : Set oWmiService = _
        GetObject("winmgmts:{impersonationLevel=impersonate}!\\" _
                  & sComputer & "\root\cimv2")

    Dim cTimeZone : Set cTimeZone = _
        oWmiService.ExecQuery("Select * from Win32_TimeZone")

    Dim oTimeZone
    For Each oTimeZone in cTimeZone
        GetTimeZoneOffset = oTimeZone.Bias / 60
        Exit For
    Next
End Function