Daylight Savings Time Check in Oracle

I needed a way to find if a given date is within a DST date range.  We observe DST here, so I needed to know if I needed to adjust the time or not.  The main purpose was so I could convert a date/time to GMT, which does not observe DST.

First column is current date/time
DST_START is the day DST starts
DST_END is the day DST ends
DST_CHECK will be “Y” if we are currently in DST, “N” if not.
CURRENT_TIME_GMT converts the current time to what it would be in GMT

SELECT SYSDATE,
NEXT_DAY (
TO_DATE (TO_CHAR (SYSDATE, 'YYYY') || '/03/01 02:00 AM',
'YYYY/MM/DD HH:MI AM')
- 1,
'SUN')
+ 7
dst_start,
NEXT_DAY (
TO_DATE (TO_CHAR (SYSDATE, 'YYYY') || '/11/01 02:00 AM',
'YYYY/MM/DD HH:MI AM')
- 1,
'SUN')
dst_end,
CASE
WHEN SYSDATE >=
NEXT_DAY (
TO_DATE (
TO_CHAR (SYSDATE, 'YYYY')
|| '/03/01 02:00 AM',
'YYYY/MM/DD HH:MI AM')
- 1,
'SUN')
+ 7
AND SYSDATE <
NEXT_DAY (
TO_DATE (
TO_CHAR (SYSDATE, 'YYYY') || '/11/01 02:00 AM',
'YYYY/MM/DD HH:MI AM')
- 1,
'SUN')
THEN
'Y'
ELSE
'N'
END
AS dst_check,
NEW_TIME (
SYSDATE,
CASE
WHEN SYSDATE >=
NEXT_DAY (
TO_DATE (
TO_CHAR (SYSDATE, 'YYYY')
|| '/03/01 02:00 AM',
'YYYY/MM/DD HH:MI AM')
- 1,
'SUN')
+ 7
AND SYSDATE <
NEXT_DAY (
TO_DATE (
TO_CHAR (SYSDATE, 'YYYY')
|| '/11/01 02:00 AM',
'YYYY/MM/DD HH:MI AM')
- 1,
'SUN')
THEN
'CDT'
ELSE
'CST'
END,
'GMT')
AS current_time_gmt
FROM DUAL;

To give credit, I used the info from:
https://www.techonthenet.com/oracle/functions/new_time.php
https://stackoverflow.com/questions/287563/in-oracle-how-can-i-detect-the-date-on-which-daylight-savings-time-begins-end