One Weekly Meeting, Three Cities: Auckland, London and New York Through the 2026 Clock Changes

By Paul Clark October 13, 2026 8 min read timezoneschedulingplanning

Hana runs product for a small software company from Auckland. Her designer, Tom, is in London and the engineering lead, Marcus, is in New York. They hold one live meeting a week, a 45-minute planning call, and every spring and autumn it breaks for a fortnight because three governments move their clocks on three different Sundays.

In the second half of 2026 those Sundays are:

27 September 2026: New Zealand starts daylight time at 2am (NZST, UTC+12, becomes NZDT, UTC+13). The rule is the last Sunday in September, per the New Zealand Government daylight saving page.
25 October 2026: the UK goes back an hour (BST, UTC+1, becomes GMT, UTC+0), per gov.uk.
1 November 2026: the US goes back at 2am (EDT, UTC-4, becomes EST, UTC-5), under the first-Sunday-in-November rule in 15 U.S.C. 260a.

The fix for a sane meeting is mostly a decision about which city owns the clock. The three calculators below help you make that decision with real numbers, and each one has a blind spot you need to know about before trusting it.

The meeting through the season

The team pinned the call to Tuesday 09:00 Auckland time. Hana leads it, it sits at the start of her working day, and it keeps both of the other ends before 22:00. Here is what that one fixed Auckland time means at the other two ends. Every row was checked against the IANA time-zone rules in Node's Intl implementation, the same data the calculators use.

Period	Auckland	London	New York
Until Sat 26 Sep 2026	Tue 09:00 NZST	Mon 22:00 BST	Mon 17:00 EDT
27 Sep to 24 Oct	Tue 09:00 NZDT	Mon 21:00 BST	Mon 16:00 EDT
25 Oct to 31 Oct	Tue 09:00 NZDT	Mon 20:00 GMT	Mon 16:00 EDT
1 Nov 2026 to 13 Mar 2027	Tue 09:00 NZDT	Mon 20:00 GMT	Mon 15:00 EST
14 Mar to 27 Mar 2027	Tue 09:00 NZDT	Mon 20:00 GMT	Mon 16:00 EDT
28 Mar to 3 Apr 2027	Tue 09:00 NZDT	Mon 21:00 BST	Mon 16:00 EDT
From 4 Apr 2027	Tue 09:00 NZST	Mon 22:00 BST	Mon 17:00 EDT

Two things jump out. First, the meeting is on a Tuesday for one person and a Monday for the other two, every single week. Second, the London end moves by two hours over the year and the New York end by two hours as well, but not in step. The spring 2027 dates (US forward on 14 March, UK forward on 28 March, NZ back on 4 April) come from the same three sources.

Step 1: measure the overlap pair by pair

The Timezone Working Hours Overlap calculator takes a reference date, two zones and a working window, and counts the hours when both sides are inside it. It builds that answer from the browser's Intl time-zone data in 15-minute steps, so daylight saving is applied for the date you enter. Running each pair on a 9:00 to 17:00 window, one Tuesday (in Auckland) either side of each change:

Reference date	Auckland and New York	London and New York
Tue 22 Sep 2026	0 hours	3 hours (14:00 to 17:00 London)
Tue 20 Oct 2026	1 hour (09:00 to 10:00 Auckland = 16:00 to 17:00 New York)	3 hours
Tue 27 Oct 2026	1 hour	4 hours (13:00 to 17:00 London = 09:00 to 13:00 New York)
Tue 3 Nov 2026	2 hours (09:00 to 11:00 Auckland = 15:00 to 17:00 New York)	3 hours

So New Zealand's spring change is what created the Auckland and New York hour in the first place, and the US change on 1 November doubled it. London and New York get a bonus hour for one week only, between the UK change and the US one. Auckland and London never share a nine-to-five hour at any point in the year. That last result is the one that decides the meeting design: any three-way call puts London outside its working day.

To see how far outside, widen the window. With 8:00 to 21:00 entered (the tool applies the same window to both ends), London against Auckland on Monday 2 November 2026 gives 2 hours: 19:00 to 21:00 London, 08:00 to 10:00 Auckland. That is the honest shape of the team's week. The call fits only if Tom takes it in his evening, and it gets one hour later for him in the weeks before 25 October.

Two output details to read carefully:

The second zone's times have no date. With Auckland as "your zone" and 20 October as the date, the tool reports New York's overlap as 16:00 to 17:00. That is 16:00 on Monday 19 October in New York. The tool keeps only hours that fall on the reference date in your own zone, so swapping the zones changes which day you are asking about, not just the labels.
The overlap can come in two pieces. London against Auckland on Monday 19 October with an 8:00 to 21:00 window reports "2 hours of overlap" in 2 separate blocks: 08:00 to 09:00 and 20:00 to 21:00 London, one hour at the start of London's day (Auckland's evening) and one at the end (Auckland's next morning). Neither block is long enough for a standing meeting on its own.

The piece on the overlap window and daylight-saving drift covers the London and New York pairing in more depth; the three-city case is where it stops being an inconvenience and becomes a design choice.

Step 2: confirm the date each person is on

The International Business Day Converter answers a narrower question: for one calendar date, what date is it in eight fixed cities? It takes only a date, uses the instant at 00:00 UTC on that date, and lists UTC, New York, Los Angeles, London, Paris, Tokyo, Singapore and Sydney. For 27 October 2026 it returns Oct 26 for New York and Los Angeles and Oct 27 everywhere else.

That is a useful sanity check on the rollover, and it is all this tool can do for this team. It has no time input, so it cannot express "Tuesday 09:00 in Auckland", which is 20:00 UTC on Monday. It does not list Auckland. Sydney is not a stand-in: on 27 October it is two hours behind Auckland (07:00 AEDT when Auckland is at 09:00), and in late September, before Sydney's own change, it is three hours behind. Use the converter to remind everyone that a "Tuesday" deadline set from Auckland is a Monday in New York; use the overlap tool or your calendar software for the actual time. The explainer on reading one date across time zones covers why a date without a zone is ambiguous.

Step 3: generate the series, then check it against the right calendars

The Recurring Meeting Date Generator produces a run of dates spaced a set number of business days apart. With a start of Tuesday 13 October 2026, an interval of 5 and 12 occurrences, the holiday calendar you pick changes the series completely:

New Zealand calendar: Oct 13, Oct 20, then Oct 28, Nov 4, Nov 11 and onwards on Wednesdays, then Dec 23 and Jan 5, 2027. Labour Day (Monday 26 October) removes a business day, so every later meeting slides a day until the Christmas closures happen to push it back to a Tuesday.
US calendar: Oct 13, 20, 27, Nov 3, Nov 10, then Nov 18 (Veterans Day on Wednesday 11 November costs a day), Nov 25, then Dec 3 after Thanksgiving, and so on.
UK calendar: Tuesdays through Dec 22, then Dec 31.

That is the generator doing exactly what it says: the interval is counted in business days, not weeks. It is the right tool for "a checkpoint every five working days" and the wrong one for "every Tuesday". The calculator's own page notes that it does not implement the iCalendar recurrence grammar, so there is no weekday-based rule to pick; the post on business-day meeting series explains the design.

For a fixed weekly slot, clear the holiday calendar. With no country selected, the same input gives a clean run of 20 Tuesdays from 13 October 2026 to 23 February 2027. Then check holidays by hand, and here the rollover matters again: the Auckland Tuesday is a Monday in London and New York, so you check Tuesday holidays for Hana and Monday holidays for Tom and Marcus.

Tue 13 Oct: Monday 12 October is Columbus Day in the US. Federal offices are closed; most private companies are not.
Tue 29 Dec: Monday 28 December is the Boxing Day substitute bank holiday in England and Wales (gov.uk bank holidays) and Boxing Day observed in New Zealand for staff who don't normally work Saturdays.
Tue 19 Jan 2027: Monday 18 January is Martin Luther King Jr. Day.
Tue 16 Feb 2027: Monday 15 February is Washington's Birthday (both on OPM's federal holiday list).

None of New Zealand's national holidays in this run fall on a Tuesday (Employment New Zealand), so Hana never loses a meeting to her own calendar. All the cancellations are Monday holidays at the other end, which no single-country run of the generator would show you.

Where the tools stop

The overlap tool compares two zones at a time and uses one working window for both. Three-way overlap means running three pairs and intersecting them yourself.
It works in 15-minute steps, so half-hour zones come out right: London against Asia/Kolkata on 20 October gives three and a half hours, 13:30 to 17:00 in Kolkata. (Until October 2026 it stepped in whole hours and reported 4; the fix is on the changes page.)
It ignores public holidays, as its page says.
The converter has no times and no Auckland.
The generator uses one holiday calendar and counts business days. It produces calendar dates with no time or zone; the invitation itself still has to be created in a calendar app.
None of them warn you that a clock change is coming. You have to check dates either side of each transition yourself, which is what the table above does.

The setup that held up

Create the invitation in the Pacific/Auckland zone, because Hana's time is the fixed point. Calendar software then moves London and New York automatically on 25 October and 1 November.
Tell Tom and Marcus their times will change twice in five weeks, and when: 21:00, then 20:00 for Tom; 16:00, then 15:00 for Marcus.
Run the overlap tool on one date inside each period, not one date for the whole season.
Generate the series with no holiday calendar, then check Tuesday holidays in New Zealand and Monday holidays in the UK and US.
Put the spring dates (14 March, 28 March and 4 April 2027) in the diary now; the same pattern runs in reverse.