Guides

Long-form guides

Time zones, DST, and async-first remote work. Each guide is opinionated, written for people who schedule across countries for a living, and updated yearly.

Time zones · 16 June 2026
When do the clocks change in 2026? DST dates by country
A clean dated lookup: the exact spring-forward and fall-back dates for the US, UK, EU, Canada, Australia and New Zealand, which way the clocks move, the countries that no longer change, and the 2027 dates.
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Developer reference · 16 June 2026
Cron expression examples — every common schedule, explained
A working reference for the cron schedules people actually write: every few minutes, hourly, at a fixed time each day, on a given weekday, and the awkward monthly and special-character cases. Each example links to a live next-run preview and copy-ready expressions for seven scheduler dialects.
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Time zones · 28 May 2026
Best time to call London from New York — 2026 guide
The textbook answer is 9 AM ET. The textbook is sometimes wrong. A practical guide to the five-hour gap, DST cliffs, and the late-day window that beats them both.
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Time zones · 28 May 2026
Daylight saving 2026 survival guide — every date that matters
Every DST transition in 2026 for the US, EU, UK, Australia, and New Zealand. Why recurring calendar invites silently break around the transitions, and how to stop them.
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Remote work · 28 May 2026
The async-first standup playbook — replace the 15-minute call
A 15-minute standup with six engineers costs $36,000 a year. Here is how to replace it without losing the visibility — and the small set of cases where the meeting still wins.
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Time zones · 28 May 2026
Time zone abbreviations — the reference every scheduler needs
EST, EDT, PST, GMT, BST, CET, CEST, IST. The abbreviations every email signature uses, the ones that mean two different things in two different countries, and the ones to never use in a calendar invite.
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Remote work · 28 May 2026
Public holidays for distributed teams — a 2026 calendar
Eighteen countries, every observed public holiday in 2026, and the ones that matter for sales calls, payroll cutoffs, and on-call rotations. The thing your HRIS will not tell you.
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Developer reference · 29 May 2026
Date and time format style guide — ISO 8601, RFC 3339, SQL, Unix
The opinionated developer reference for date and time formats. When to use ISO 8601, when to use RFC 3339, when epoch ms wins, what SQL TIMESTAMPTZ actually does, and the anti-patterns that will burn you.
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Time zones · 29 May 2026
Time zones, explained — the IANA tzdb, DST, and why your code keeps breaking
Why time zones exist, how the IANA database works under the hood, half-hour and 45-minute offsets, the DST abolition debates, and what Zeitful's tools do with the data. The long-read primer for people who schedule and write code across countries.
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Developer reference · 29 May 2026
JavaScript date and time — Temporal, date-fns, Luxon, timezones
The opinionated developer reference for handling dates in JavaScript. Why the legacy Date object hurts, how Temporal fixes it, which library to pick today, and the timezone and DST patterns that survive production.
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Calendars · 29 May 2026
Calendar reform history — Julian, Gregorian, French Republican, Soviet, and the ones that failed
From Caesar's 46 BCE fix to Gregory's eleven-day cut, the English riot myth of 1752, the French decimal experiment, the Soviet five-day week, Ethiopia's thirteen months, and the modern proposals nobody adopted. A practical history of why calendars keep getting reformed and what survives the attempt.
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Developer reference · 29 May 2026
Date formats by country — DMY, MDY, YMD reference for 99 countries
The complete country-by-country reference. Why the US writes 3/14/2026 while the UK writes 14/03/2026 and Japan writes 2026/03/14, what national standards body defines each convention, and the sortable table that settles every locale argument.
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Calendars · 29 May 2026
Etymology of the months — Janus, Februa, Caesar, Augustus, and the off-by-two Romans
Where the month names come from. The Greek and Etruscan ten-month calendars, Numa's reform around 715 BCE, the gods behind January through June, why two emperors got their own months in the middle of summer, and why September through December are still numbered as if it were 700 BCE.
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Science · 29 May 2026
Time in physics — the second, relativity, atomic clocks, and the arrow of time
What time actually is, as physics currently understands it. The SI definition of the second, Newton's absolute time, Einstein's special and general relativity, the atomic clocks accurate to one second in fourteen billion years, why leap seconds exist and why we are getting rid of them, the four arrows of time, and the Planck-scale limit where the equations stop.
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Science · 29 May 2026
Time perception — how humans and animals experience time differently
The clock on the wall ticks at a constant rate. Felt time does not. A long-form science guide to the gap between objective and subjective duration: the suprachiasmatic nucleus, why time accelerates with age, why a fly sees the world four times slower than you do, the dopamine clock, trauma and flow, jet lag and shift work, monochronic versus polychronic cultures, and what any of it means for getting through a Tuesday.
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Horology · 29 May 2026
History of clocks — sundials to atomic, 3500 BCE to the optical lattice
Five and a half millennia of timekeeping technology. Babylonian shadow sticks, Greek water clocks, the verge escapement in Italian monasteries, Huygens's pendulum, Harrison's H4 and the £20,000 longitude prize, the 1969 quartz wristwatch revolution, caesium and strontium, and the nuclear clocks that will probably succeed them.
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Time zones · 29 May 2026
Political time zones — how governments redrew the global clock
Geography would give us 24 time zones. Politics gave us 40. China's one-zone empire, Franco's CET realignment, Samoa skipping a calendar day, North Korea's Pyongyang Time, India's half-hour, Russia's eleven, Arizona's exception, Bolivia's backward clock, and the EU's stalled vote to abolish DST.
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When do the clocks change in 2026? DST dates by country

Cron expression examples — every common schedule, explained

Best time to call London from New York — 2026 guide

Daylight saving 2026 survival guide — every date that matters

The async-first standup playbook — replace the 15-minute call

Time zone abbreviations — the reference every scheduler needs

Public holidays for distributed teams — a 2026 calendar

Date and time format style guide — ISO 8601, RFC 3339, SQL, Unix

Time zones, explained — the IANA tzdb, DST, and why your code keeps breaking

JavaScript date and time — Temporal, date-fns, Luxon, timezones

Calendar reform history — Julian, Gregorian, French Republican, Soviet, and the ones that failed

Date formats by country — DMY, MDY, YMD reference for 99 countries

Etymology of the months — Janus, Februa, Caesar, Augustus, and the off-by-two Romans

Time in physics — the second, relativity, atomic clocks, and the arrow of time

Time perception — how humans and animals experience time differently

History of clocks — sundials to atomic, 3500 BCE to the optical lattice

Political time zones — how governments redrew the global clock

When do the clocks change in 2026? DST dates by country

Cron expression examples — every common schedule, explained

Best time to call London from New York — 2026 guide

Daylight saving 2026 survival guide — every date that matters

The async-first standup playbook — replace the 15-minute call

Time zone abbreviations — the reference every scheduler needs

Public holidays for distributed teams — a 2026 calendar

Date and time format style guide — ISO 8601, RFC 3339, SQL, Unix

Time zones, explained — the IANA tzdb, DST, and why your code keeps breaking

JavaScript date and time — Temporal, date-fns, Luxon, timezones

Calendar reform history — Julian, Gregorian, French Republican, Soviet, and the ones that failed

Date formats by country — DMY, MDY, YMD reference for 99 countries

Etymology of the months — Janus, Februa, Caesar, Augustus, and the off-by-two Romans

Time in physics — the second, relativity, atomic clocks, and the arrow of time

Time perception — how humans and animals experience time differently

History of clocks — sundials to atomic, 3500 BCE to the optical lattice

Political time zones — how governments redrew the global clock