This spring's *Weeks of Confusion* will start on this Sunday, 2025-03-09, and end on Sunday, 2025-03-30. (There also will be a single week of confusion in the fall, 2025-10-26 to 2025-11-02.) The US and CA will switch to DST on 2025-03-09, and the EU will follow with their DST in 2025-03-30. In the three weeks in between, extra care needs to be taken in scheduling meetings, as the time zone gap will be one hour less. IETF 122 will be entirely in these weeks. So the time zone offsets between EU and US, which are stable for ~48 weeks of the year, shift for these weeks: E.g.: San Francisco (going to PDT on Sunday) will be 8 hours behind Berlin (staying CET), not the usual 9. (There will be one more week of confusion in the fall, between end of EU DST 2025-10-26 and end of US/CA DST 2025-11-02 — again, only 8 hours between SFO and BER. IETF 124 Hackathon Saturday will be in that time, while we’ll have the usual time zone distance during the rest of IETF 124.) If you have a periodic meeting in these weeks, check whether it is anchored to US/CA time, in which case the meeting starts one hour earlier than usual in EU, or whether it is anchored to EU time, in which case it starts one hour later than usual in the US/CA. (If anchored to world time, UTC, each region changes along their own DST schedule.) The spring and fall IETF meetings and the weeks around those always touch the weeks of confusion, so we all have to be alert. Use .ics files to announce meetings as much as possible, after verifying them... Grüße, Carsten (Apologies to everyone not living in the US/CA or EU — I didn’t want to make this message any longer with more cases, e.g., MX and much of Asia do not observe DST any more/at all, and AU/NZ of course switch the other way around, at different times (!). And Europe has countries/regions without DST as well, e.g., Iceland or Moscow.)
