Determine if given date is within DST clock shift - SQL Scalar Function

IsDaylightSavingTime

SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
-- =============================================
-- Author:	Carol Ouellet
-- Create date: 2017-04-21
-- Description:	Determine if given date is within DST clock shift
-- =============================================
CREATE FUNCTION IsDaylightSavingTime 
(
	-- Add the parameters for the function here
	@DateToCheck varchar(255)
)
RETURNS BIT
AS
BEGIN
	-- Declare the return variable here
	DECLARE @IsDST BIT

	-- Add the T-SQL statements to compute the return value here
	Declare @DstEnd datetime;
with FirstWeekOfNovember
   as (
       select top(7)
              cast(YEAR(@DateToCheck) as char(4))
            + '-11-0'
            + cast(row_number() over(order by object_id) as char(1))
            + ' 02:00:00'
              'DST_Stops'
         from sys.columns
      )
   select @DstEnd = DST_Stops
     from FirstWeekOfNovember
    where datepart(weekday,DST_Stops) = 1


Declare @DstStart datetime;
   ;with FirstWeekOfNovember
   as (
       select top(7)
              cast(Year(@DateToCheck) as char(4))
            + '-11-0'
            + cast(row_number() over(order by object_id) as char(1))
            + ' 02:00:00'
              'DST_Stops'
         from sys.columns
      )
   select @DstStart = dateadd(day,-238,DST_Stops)
     from FirstWeekOfNovember
    where datepart(weekday,DST_Stops) = 1

	-- Return the result of the function
	RETURN 	CASE
    WHEN @DateToCheck > @DstStart AND @DateToCheck < @DstEnd THEN 1
    ELSE 0
	END
END
GO