US House to vote on bill to make daylight saving time permanent
Article: https://www.reuters.com/world/us/us-house-vote-bill-make-daylight-saving-tim... 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 Jacob Pratt
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-tim...
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.
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-tim...
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
On 7/10/2026 1:08 PM, Brooks Harris via tz wrote:
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
Downstream programs should be able to handle "permanent standard time" easier than "permanent daylight time". The US proposal will result in "permanent standard time" with a redefinition of the offsets. -5:00 US E%sT 2027 Nov 6 -4:00 US EST -6:00 US C%sT 2027 Nov 6 -5:00 US CST -7:00 US M%sT 2027 Nov 6 -6:00 US MST -8:00 US P%sT 2027 Nov 6 -7:00 US PST The bad news is the previously mentioned current no DST states. (Such as Arizona ... will they be moved into PST UTC-07 instead of having a separate definition of MST?) And then look to Canada and Mexico. So far (one province - Saskatchewan) their "permanent daylight time" has been recognized as the standard time of the zone to the east. Saskatchewan moved from MST/MDT to CST and that seemed to be accepted. Alberta's move from PST/MDT to CST is modeled after Saskatchewan. In tzdata British Columbia's move from PST/PDT to MST follows what was done for Yukon and eastern British Columbia (with that labeling supported by the National Research Council Canada - at least through 2022). IF the US passes this law then we will have MST in Canada be a different definition than MST in the US. Getting confirmation of when the zones will actually change seems difficult. Zones officially changing "today" (instead of "effective November 1st") adds complexity. Each province and territory wanting to call their zone a different name adds complexity (at least for the downstream). Perhaps Yukon Time, British Columbia Time, Alberta Time, Saskatchewan Time, Manitoba Time would be the best answer to the problem. All we need now is common use. At least the US Law has central control of the zone definitions, both the offsets and names. I see that as good.
participants (3)
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Brooks Harris -
Jacob Pratt -
James Bellaire