Blog, 2026-07-16

Your 6pm is someone's 3am: group scheduling across time zones

How Timeheat shows every poll in the reader's own time zone, so nobody does timezone math and nobody shows up a day late.

Every distributed group has lived this one. Someone posts "call at 6pm?" and three people show up at three different times. One of them did the math backwards across a date line and joined a day early. Nobody was careless; timezone arithmetic is just a terrible job to give humans.

The usual workarounds don't hold up

Most groups try one of three things. They pin everything to the organizer's zone and make everyone else convert ("all times in CET!"), which works right up until someone forgets. They paste a row of conversions into the invite ("6pm CET / 12pm EST / 9am PST"), which goes stale the moment a daylight-saving switch lands on one side of the ocean but not the other. Or they use a scheduling tool that shows everyone the same wall-clock grid and quietly hope.

What timeheat does instead

A timeheat poll has one home time zone, the one the organizer picked when creating it. That's the only clock the poll stores. Then every person who opens the poll sees the grid in their own zone. Your respondent in Buenos Aires paints their afternoon; your respondent in Berlin sees that same availability land in their evening. Nobody converts anything, because nobody ever sees a foreign clock.

The detection is automatic (the browser knows its zone), and signed-in users can pin a preferred zone in settings for when they travel. Daylight saving is handled the only sane way: each conversion happens on the actual date of the slot, so a poll that straddles a DST switch stays correct on both sides of it.

Down to the calendar invite

When the organizer picks the final time, the poll page offers add-to- calendar buttons for Google, Outlook, and Apple. The .ics file carries the proper timezone identifier rather than a naive timestamp, so the event lands at the right local hour for every attendee, wherever their calendar lives.

After that there isn't much story left. The group answers in minutes, the heatmap shows where everyone overlaps, and the 6pm/3am screwup can't happen, because nobody did any arithmetic to get it wrong.