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Gravitational wave detectors affected by DST
by Paul Eggert March 2, 2026

March 2, 2026

An astronomy paper published in January ties daylight saving time to LIGO, the Laser Interferometer Gravitational-Wave Observatory, which detects cosmic gravitational waves. Here's a citation: Essick R. Can LIGO Detect Daylight Saving Time? ApJ. 2026;997:76. <https://doi.org/10.3847/1538-4357/ae2255>. The answer to the paper's title is "yes". Gravitational wave detectors, though designed to detect black holes merging billions of light years from here, can also distinguish Earth day from Earth night, weekends from weekdays, and even daylight saving from standard time. This is because their human operators and neighbors generate noise that significantly affects the detectors' sensitivity, and the noise itself can be analyzed to detect human-caused patterns like DST. This has consequences for the conclusions that can be drawn from LIGO surveys. For a readable summary of Essick's results, see: Tomaswick A. Gravitational wave detectors affected by daylight savings time. Universe Today. 2025-09-25. <https://phys.org/news/2025-09-gravitational-detectors-affected-daylight.html>.

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[PROPOSED] The CIA World Factbook is no more
by Paul Eggert March 1, 2026

March 1, 2026

* tz-link.html: The CIA World Factbook sunsetted on 2026-02-04. Downgrade its citation accordingly. --- tz-link.html | 29 +++++++++++------------------ 1 file changed, 11 insertions(+), 18 deletions(-) diff --git a/tz-link.html b/tz-link.html index acc2df58..f19f9aab 100644 --- a/tz-link.html +++ b/tz-link.html @@ -742,31 +742,24 @@ gives current time zone rules for airports served by commercial aviation.</li> <section> <h2 id="maps">Maps</h2> <ul> -<li>The <a -href="https://www.cia.gov/the-world-factbook/maps/world-regional/">World -and Regional Maps section</a> of <em>The World Factbook</em>, published by the -<a href="https://www.cia.gov">US Central Intelligence -Agency (<abbr -title="Central Intelligence Agency">CIA</abbr>)</a>, contains a time -zone map; the -<a -href="https://maps.lib.utexas.edu/maps/world.html">Perry–Castañeda -Library Map Collection</a> -of the University of Texas at Austin has copies of -recent editions. -The pictorial quality is good, -but the maps do not indicate daylight saving time, -and parts of the data are a few years out of date.</li> <li><a href="https://www.worldtimezone.com">World Time Zone Map with current time</a> -has several fancy time zone maps; it covers Russia particularly well. -The maps’ pictorial quality is not quite as good as the <abbr>CIA</abbr>’s -but the maps are more up to date.</li> +has several fancy time zone maps; it covers Russia particularly well.</li> <li><a href="https://blog.poormansmath.net/how-much-is-time-wrong-around-the-world/">How much is time wrong around the world?</a> maps the difference between mean solar and standard time, highlighting areas such as western China where the two differ greatly. It’s a bit out of date, unfortunately.</li> +<li>The +<a +href="https://maps.lib.utexas.edu/maps/world.html">Perry–Castañeda +Library Map Collection</a> of the University of Texas at Austin has +copies of old maps taken from <a +href="https://en.wikipedia.org/wiki/The_World_Factbook"><em>The +World Factbook</em></a>, formerly published by the +<a href="https://www.cia.gov">US Central Intelligence Agency</a>. +Although the maps’ pictorial quality is good, +the maps do not indicate daylight saving time.</li> </ul> </section> -- 2.51.0

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[PROPOSED] Pacify clang -Wunterminated-string-initialization
by Paul Eggert March 1, 2026

March 1, 2026

* private.h (ATTRIBUTE_NONSTRING): Also define for Clang 21+. --- private.h | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/private.h b/private.h index 6a58b073..ee191b4e 100644 --- a/private.h +++ b/private.h @@ -539,9 +539,12 @@ typedef unsigned long uintmax_t; # define HAVE___HAS_C_ATTRIBUTE false #endif -#if 8 <= __GNUC__ -# define ATTRIBUTE_NONSTRING __attribute__((__nonstring__)) -#else +#ifdef __has_attribute +# if __has_attribute (nonstring) +# define ATTRIBUTE_NONSTRING __attribute__((__nonstring__)) +# endif +#endif +#ifndef ATTRIBUTE_NONSTRING # define ATTRIBUTE_NONSTRING #endif -- 2.53.0

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Request to Add Bukavu or Goma to the IANA Africa/ Time Zone Database
by Marcel Shabani Feb. 28, 2026

Feb. 28, 2026

Dear IANA Time Zone Database Team, My name is Marcel Shabani, a software developer from the Democratic Republic of the Congo (DRC). I am writing to kindly request consideration for the inclusion of Bukavu or Goma as distinct representative locations under the Africa/ region in the IANA Time Zone Database. Currently, many systems default to Africa/Lubumbashi for regions in the eastern DRC. But, cities like Bukavu<https://en.wikipedia.org/wiki/Bukavu> and Goma<https://en.wikipedia.org/wiki/Goma> are geographically distant from Lubumbashi and represent significantly different parts of the country. Having a more locally relevant TZ identifier (e.g., Africa/Bukavu or Africa/Goma) would greatly improve accuracy for residents, developers, and organizations operating in these regions. I understand that the TZ Database prioritizes representation rather than exhaustive listings, but adding one of these major cities would help ensure better alignment with real-world usage across eastern DRC. Thank you for your time, and I appreciate your continued work in maintaining this globally important resource. I am happy to provide any additional information if needed. Kind regards, Marcel Shabani -- Marcel Baguma Shabani Managing Director Tuunganes marcel.shabani(a)tuunganes.com | <https://teams.microsoft.com/l/chat/0/0?users=mshabani@ctrl-qs.com> Contact in Teams<https://teams.microsoft.com/l/chat/0/0?users=marcel.shabani@tuunganes.com> 006K, Avenue Pere Georges Defour Bukavu DRCongo https://tuunganes.com [cid:05ebfea4-d90b-40bb-b78f-ee12a0668f21]<https://outlook.office.com/bookwithme/user/c8100903c3844ae28a49622612817121…> Book time to <https://outlook.office.com/bookwithme/user/c8100903c3844ae28a49622612817121…> discuss | Prendre rendez-vous

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Bill for "half-daylight time" proposed in US House
by Tim Parenti Feb. 26, 2026

Feb. 26, 2026

With the annual clock changes soon approaching, we are well-accustomed by now to discussion picking back up around the typical proposals for "permanent daylight time" and "permanent standard time". But an alternative proposal of "permanent half-daylight time" has now been put forth in the US House of Representatives. For example, "Eastern time would then be 4.5 hours behind UTC, instead of five." Republican representative Greg Steube, who represents the Sarasota area in southwest Florida's 17th district, introduced HR 7378 (the "Daylight Act of 2026") on 4 February 2026. The bill was referred to the House Committee on Energy and Commerce but, like most such proposals, has not yet moved forward. As presently drafted, the bill provides that the changes would take effect only 90 days after enactment. https://www.usatoday.com/story/news/nation/2026/02/19/daylight-act-of-2026-… https://www.congress.gov/bill/119th-congress/house-bill/7378/text https://www.congress.gov/119/bills/hr7378/BILLS-119hr7378ih.pdf -- Tim Parenti

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daylight savings changes in Nunavimmiut?
by Antoine Beaupré Feb. 26, 2026

Feb. 26, 2026

Hi, I'm writing to enquire about this news article you wrote back in November: https://www.cbc.ca/news/canada/north/nunavik-daylight-savings-9.6969650 From what I gathered while reading the article, Nunavik would not change their clocks back to normal time in the fall, after this summer's daylight savings, staying permanently on "normal" time. This has significant implication in the software world: changes like this must be coordinated across different engineers. Specifically, the "Time Zone Database" (tzdb) needs to be updated to reflect those changes. Right now, the only information regarding this change is your news article, and it doesn't make it solidly clear that this is actually happening. I have actually tried calling Makivvik and, while people were busy with a meeting there, the secretary that answered didn't seem aware of the change. This makes me doubt the change will actually happen. Do you have more information about the upcoming change? Anyone we could contact to confirm this information first hand? See also: https://lists.iana.org/hyperkitty/list/tz@iana.org/thread/6HN5SWD2BJA7OVTPF… Thanks, a. -- Antoine Beaupré Debian Developer

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[PROPOSED 1/2] Pacify GCC 15.2 -Wzero-as-null-pointer-constant
by Paul Eggert Feb. 24, 2026

Feb. 24, 2026

* localtime.c (time): Use NULL, not 0, for null pointer. --- localtime.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/localtime.c b/localtime.c index 32835d08..0091b81e 100644 --- a/localtime.c +++ b/localtime.c @@ -3135,7 +3135,7 @@ posix2time(time_t t) time_t time(time_t *p) { - time_t r = sys_time(0); + time_t r = sys_time(NULL); if (r != (time_t) -1) { iinntt offset = EPOCH_LOCAL ? timezone : 0; if (offset < IINNTT_MIN + EPOCH_OFFSET -- 2.51.0

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Re: Bill for "half-daylight time" proposed in US House
by Doug Ewell Feb. 20, 2026

Feb. 20, 2026

World Time Zone wrote: > Maybe we should leave clocks and time zones alone and just shift work, > school, and service times by 30 minutes? If every business, school, and service entity shifted its times uniformly, then this would work, and would be effectively equivalent to having the government set the time as we do now. Anything short of complete uniformity would blow the plan. From the mid-1950s to the mid-1980s, there was a tourist attraction in Buena Park called California Alligator Farm. One of their business cards showed that their hours of operation were 11 am to 5 pm during standard time, and noon to 6 pm during DST. Alligators don’t change their circadian rhythms when humans change their clocks. A tourist attraction can get away with this, in a way that schools and workplaces and businesses and daycare centers and everyone else whose schedules depend on each other cannot. -- Doug Ewell, CC, ALB | Lakewood, CO, US | ewellic.org

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Re: Downloads from data.iana.org now seem to be sensitive to the User-Agent value supplied in HTTP request headers
by James Mitchell Feb. 4, 2026

Feb. 4, 2026

Hi Johny, I’m sorry you are having issues downloading the tz data. There should have been no changes to access restrictions via user agent or other attributes. I’ll investigate this and get back to you. Thanks, James Mitchell IANA From: Johny Jose via tz <tz(a)iana.org> Reply-To: Johny Jose <johny.jose(a)oracle.com> Date: Tuesday, February 3, 2026 at 4:20 PM To: "tz(a)iana.org" <tz(a)iana.org> Subject: [tz] Downloads from data.iana.org now seem to be sensitive to the User-Agent value supplied in HTTP request headers Hi, I am reaching out regarding an issue encountered while attempting to download the latest tzdata release (tzdata2025c.tar.gz) from https://data.iana.org/time-zones/releases/tzdata2025c.tar.gz using Java JDK 8’s HTTP request API. We use the tzupdater tool (https://www.oracle.com/java/technologies/javase/tzupdater-readme.html [oracle.com]<https://urldefense.com/v3/__https:/www.oracle.com/java/technologies/javase/…>) to update the jdk to latest tzdata. Since Monday, January 26, 2026, we have been facing issues while downloading tzdata2025c.tar.gz. We are receiving an HTTP 403 error response from the server. This appears to be due to a validation failure related to the HTTP header User-Agent (specifically, User-Agent: Java/1.8.0_471). User-Agent values from JDK 11 and later (e.g. User-Agent: Java/11.0.16) do not trigger this issue. Could you kindly advise on the following: Has there been a specific format restriction enabled for the User-Agent value string to grant access? If so, is it possible to whitelist widely used Java-based User-Agent strings? Error Logs: sun.net.www.protocol.http.HttpURLConnection sendCONNECTRequest FINE: sun.net.www.MessageHeader@2f1129655<mailto:sun.net.www.MessageHeader@2f1129655> pairs: {CONNECT data.iana.org:443 HTTP/1.1: null}{User-Agent: Java/1.8.0_471}{Host: data.iana.org}{Accept: text/html, image/gif, image/jpeg, *; q=.2, */*; q=.2}{Proxy-Connection: keep-alive} Jan 30, 2026 8:07:24 AM sun.net.www.protocol.http.HttpURLConnection doTunneling FINE: sun.net.www.MessageHeader@d4342c21<mailto:sun.net.www.MessageHeader@d4342c21> pairs: {null: HTTP/1.0 200 Connection Established} Jan 30, 2026 8:07:24 AM sun.net.www.protocol.http.HttpURLConnection writeRequests FINE: sun.net.www.MessageHeader@770d33265<mailto:sun.net.www.MessageHeader@770d33265> pairs: {GET /time-zones/releases/tzdata2025c.tar.gz HTTP/1.1: null}{User-Agent: Java/1.8.0_471}{Host: data.iana.org}{Accept: text/html, image/gif, image/jpeg, *; q=.2, */*; q=.2}{Connection: keep-alive} Jan 30, 2026 8:07:24 AM sun.net.www.http.HttpClient logFinest FINEST: KeepAlive stream used: https://data.iana.org/time-zones/releases/tzdata2025c.tar.gz Jan 30, 2026 8:07:24 AM sun.net.www.protocol.http.HttpURLConnection getInputStream0 FINE: sun.net.www.MessageHeader@d4342c211<mailto:sun.net.www.MessageHeader@d4342c211> pairs: {null: HTTP/1.1 403 Forbidden}{Date: Fri, 30 Jan 2026 08:07:24 GMT}{Content-Type: text/plain; charset=UTF-8}{Content-Length: 16}{Connection: keep-alive}{Cache-Control: private, max-age=0, no-store, no-cache, must-revalidate, post-check=0, pre-check=0}{Expires: Thu, 01 Jan 1970 00:00:01 GMT}{Referrer-Policy: same-origin}{X-Frame-Options: SAMEORIGIN}{Server: cloudflare} java.io.IOException: Server returned HTTP response code: 403 for URL: https://data.iana.org/time-zones/releases/tzdata2025c.tar.gz I tried to create a new thread in tz - lists.iana.org<https://lists.iana.org/hyperkitty/list/tz@iana.org/> but could not succeed in it. Thank you for your assistance. Let me know if you would like any further information. Thanks, Johny Confidential- Oracle Internal

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Downloads from data.iana.org now seem to be sensitive to the User-Agent value supplied in HTTP request headers
by Johny Jose Feb. 3, 2026

Feb. 3, 2026

Hi, I am reaching out regarding an issue encountered while attempting to download the latest tzdata release (tzdata2025c.tar.gz) from https://data.iana.org/time-zones/releases/tzdata2025c.tar.gz using Java JDK 8's HTTP request API. We use the tzupdater tool (https://www.oracle.com/java/technologies/javase/tzupdater-readme.html) to update the jdk to latest tzdata. Since Monday, January 26, 2026, we have been facing issues while downloading tzdata2025c.tar.gz. We are receiving an HTTP 403 error response from the server. This appears to be due to a validation failure related to the HTTP header User-Agent (specifically, User-Agent: Java/1.8.0_471). User-Agent values from JDK 11 and later (e.g. User-Agent: Java/11.0.16) do not trigger this issue. Could you kindly advise on the following: Has there been a specific format restriction enabled for the User-Agent value string to grant access? If so, is it possible to whitelist widely used Java-based User-Agent strings? Error Logs: sun.net.www.protocol.http.HttpURLConnection sendCONNECTRequest FINE: sun.net.www.MessageHeader@2f1129655<mailto:sun.net.www.MessageHeader@2f1129655> pairs: {CONNECT data.iana.org:443 HTTP/1.1: null}{User-Agent: Java/1.8.0_471}{Host: data.iana.org}{Accept: text/html, image/gif, image/jpeg, *; q=.2, */*; q=.2}{Proxy-Connection: keep-alive} Jan 30, 2026 8:07:24 AM sun.net.www.protocol.http.HttpURLConnection doTunneling FINE: sun.net.www.MessageHeader@d4342c21<mailto:sun.net.www.MessageHeader@d4342c21> pairs: {null: HTTP/1.0 200 Connection Established} Jan 30, 2026 8:07:24 AM sun.net.www.protocol.http.HttpURLConnection writeRequests FINE: sun.net.www.MessageHeader@770d33265<mailto:sun.net.www.MessageHeader@770d33265> pairs: {GET /time-zones/releases/tzdata2025c.tar.gz HTTP/1.1: null}{User-Agent: Java/1.8.0_471}{Host: data.iana.org}{Accept: text/html, image/gif, image/jpeg, *; q=.2, */*; q=.2}{Connection: keep-alive} Jan 30, 2026 8:07:24 AM sun.net.www.http.HttpClient logFinest FINEST: KeepAlive stream used: https://data.iana.org/time-zones/releases/tzdata2025c.tar.gz Jan 30, 2026 8:07:24 AM sun.net.www.protocol.http.HttpURLConnection getInputStream0 FINE: sun.net.www.MessageHeader@d4342c211<mailto:sun.net.www.MessageHeader@d4342c211> pairs: {null: HTTP/1.1 403 Forbidden}{Date: Fri, 30 Jan 2026 08:07:24 GMT}{Content-Type: text/plain; charset=UTF-8}{Content-Length: 16}{Connection: keep-alive}{Cache-Control: private, max-age=0, no-store, no-cache, must-revalidate, post-check=0, pre-check=0}{Expires: Thu, 01 Jan 1970 00:00:01 GMT}{Referrer-Policy: same-origin}{X-Frame-Options: SAMEORIGIN}{Server: cloudflare} java.io.IOException: Server returned HTTP response code: 403 for URL: https://data.iana.org/time-zones/releases/tzdata2025c.tar.gz I tried to create a new thread in tz - lists.iana.org<https://lists.iana.org/hyperkitty/list/tz@iana.org/> but could not succeed in it. Thank you for your assistance. Let me know if you would like any further information. Thanks, Johny Confidential- Oracle Internal

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