On 2026-07-10 01:15 AM, James Bellaire
via tz wrote:
On 7/9/2026
9:14 PM, Jacob Pratt via tz wrote:
Article:
https://www.reuters.com/world/us/us-house-vote-bill-make-daylight-saving-time-permanent-2026-07-09/
Looking at the text of the bill itself[^1], there is no date of
effectiveness, so it would take effect immediately upon signing.
States currently not observing DST (i.e. Hawaii and most of
Arizona) can remain on standard time, but everyone else would be
advanced an hour year-round. Because no territories currently
observe DST, the bill would de facto have no effect there.
Interestingly, there is nothing that specifies whether standard
or daylight time is used in Hawaii, Arizona, and the territories
if they don't explicitly pass a bill, but I presume common sense
would prevail in that nothing changes.
A parallel bill (S.29) was introduced in the Senate.
[^1]:
https://www.congress.gov/bill/119th-congress/house-bill/139/text
When the Senate passed the 2021 version of this bill (March 15,
2022) they amended it to be effective November 5, 2023. The bill
was held in the house until the end of the session and died.
https://www.congress.gov/bill/117th-congress/senate-bill/623
The language from the bill has already passed the committee (May
21, 2026) as an amendment to another transportation bill.
https://www.congress.gov/bill/119th-congress/house-bill/7389/text
There IS wording in the bill that allows the areas currently
following standard time year round to remain on standard time, if
they choose to do so.
*(b) Standard time for certain States and
areas.*
The standard time for a State that has exempted itself from the
provisions of section 3(a) of the Uniform Time Act of 1966 (15
U.S.C. 260a(a)), as in effect on the day before the date of the
enactment of the Sunshine Protection Act of 2025, pursuant to
such section, or an area of a State that has exempted such area
from such provisions pursuant to such section, shall be, as such
State considers appropriate—
(1) the standard time for such State or area, as the case may
be, pursuant to subsection (a) of this section; or
(2) the standard time for such State or area, as the case may
be, pursuant to subsection (a) of this section as it was in
effect on the day before the date of the enactment of the
Sunshine Protection Act of 2025.
It is a messy situation since the bill effectively redefines each
time zone to be one hour less offset from UTC and ends daylight
saving time. So if Arizona decides to opt out of the change they
would be on MST (UTC-7) while the rest of the mountain time zone
would be on MST (UTC-6). Hawaii would be on HST (UTC-10) while
western Alaska would be on HST (UTC-09). Puerto Rico would be AST
(UTC-4) while Pituffik Space Base Greenland (formerly Thule Air
Force Base) would be on AST (UTC-3).
A version of this bill has been introduced in both the house and
senate every session since 2018. The 2021 version is the only one
that passed either body. That history leads me to believe that IF
it passes both bodies it will get an effective date in November
2027 - the full year notice that is requested by this list.
There have been very many opinions and reasons discussed about DST
for "permanent daylight time" v.s "permanent standard time", from
energy, to retail, to school and work times, to sleep patterns, etc.
The one topic I've not seen discussed is the technical difficulties
of implementing this "Sunshine Act" proposal. I discussed this with
Paul Eggart a couple years ago and he said something to the effect
"Whatever we do in this area is going to be a mess".
However TzDb chooses to implement it there seems to be significant
difficulties down-stream, such as Unicode CLDR and "Display names"
in all the systems. This looks to me like a huge software revision
effort with attendant costs and likely confusion and errors.
I hope other experts with more credibility and influence than i have
would try to inform the lawmakers of these potential technical
difficulties.
-Brooks Harris