What Time Does the Sabbath Start and End?

01What time does the Sabbath start? Ask your own horizon

Sunset is a precisely defined moment, which is good news: somebody has already done the hard part. The US Naval Observatory puts it at the instant the centre of the sun sits 50 arcminutes below the horizon — the sun's own radius, about 16 arcminutes, plus roughly 34 arcminutes of atmospheric refraction. Air bends light. The sun you see resting on the horizon has, geometrically, already gone, and the tables handle that for you.

What no table handles is where you are standing. Every Sabbath start time is a start time by location, and the location is your street, not your country. Time zones are political shapes rather than solar ones — Spain keeps Central European Time at roughly Britain's longitude — and even inside an ordinary zone sunset can differ by close to an hour between the eastern and western edges. Then there is your skyline: the table's sunset belongs to an idealised beach, and you are probably somewhere with a hill.

Where you get the number matters less than people fear. An almanac, the Naval Observatory's sun data service, the weather app already on your phone — all run the same geometry on your coordinates and land within a minute or two of each other. Use whichever you will actually open on a Friday afternoon. The app comparison sorts out which tools do this well and which quietly hand you somebody else's custom.

02Six o'clock is a convention, and worth naming as one

Six is tidy, and tidy matters when you are trying to get a household to stop. No lookup, no table, the same hour in July as in January. Near the equator it is close to true.

Almost everywhere else it is not. Sunset lands near six only where the day runs close to twelve hours and your clock is honest about your longitude, and those two rarely coincide. In London in late June the sun sets just after nine, so a six o'clock rule opens the seventh day more than three hours before the sun has anything to do with it — and in December, more than two hours after.

So when people ask whether the Sabbath starts at sunset or 6pm, both rules are in use and only one is watching the sun. Worth naming plainly rather than scoring points with. Households keeping a fixed hour generally know it is a convention and hold it for the routine's sake. Others hold that the boundary belongs to the sun because Scripture handed the sun that job: "from even unto even, shall ye celebrate your sabbath." — Leviticus 23:32. The sunrise reading of the same texts sits in does the biblical day start at sunset. This article does not referee it.

03The far edge, and the margins people add to it

What time does the Sabbath end on Saturday? At sunset again, about twenty-four hours later. Not exactly — consecutive sunsets drift a minute or so apart, fastest near the equinoxes, so Saturday's printed time will not match Friday's.

Jewish practice adds a margin at both ends, worth recognising even if it is not your own custom. At the front, candles are lit before sunset rather than at it — most commonly 18 minutes early, ranging up to 40 in Jerusalem. The name, tosefet Shabbat, means adding to the Sabbath: the margin makes the boundary generous rather than tight. At the back, the older marker is three medium stars, and since nobody agrees how big a medium star is, calendars turn the wait into arithmetic — nightfall at the sun 8.5 degrees below the horizon on one widespread standard, or a fixed count of minutes after sundown, up to Rabbeinu Tam's 72.

Which answers the other thing people ask. How long is the Sabbath, 24 hours? Counted sun to sun, near enough. Kept with those margins, closer to twenty-five. One tradition's customs, set out so you recognise them rather than handed to you as obligations — and what you build inside the boundary is taken up in how to keep the Sabbath.

04Daylight saving, thick cloud, and a plane at 35,000 feet

Nothing happens to the sun when the clocks change. Only the label moves — and the label is what your table prints, so on changeover weekend Friday's sunset appears an hour later, or earlier, than the Friday before, and anyone running on memory is out by an hour. In the United States the clocks go forward on the second Sunday in March and back on the first Sunday in November, with Arizona and Hawaii sitting it out. Across the EU it is the last Sundays of March and October, and the long-running proposal to stop switching has not been adopted. Same sun. Different label. The whole rule for Sabbath and daylight saving time is one line: re-check the printed sunset that week.

Cloud changes nothing, because the time comes from the sun's geometry rather than from whether you can see it. Travel is more interesting. Sunset belongs to the ground under your feet, so driving west genuinely postpones it. Fly and it turns strange: from 35,000 feet the horizon drops away beneath you and the sun stays visible long after it has set for the fields below. Travellers take the time for the ground they are over or the city they land in, and practice here varies.

Cross the date line and the whole calendar jumps. Jewish law has argued about where a halachic date line belongs since medieval authorities first raised the problem, with no unanimity yet. Communities in Japan and New Zealand keep the local Saturday, and some authorities ask travellers to observe part of the Sabbath on the neighbouring day too. Cross the Pacific often and this is a question for whoever you take counsel from, not a blog post.

05Above the Arctic Circle, where the sun stops cooperating

North of roughly 66°34', a rule that says "begin at sunset" eventually runs out of sunsets. In Svalbard the sun does not set at all for about four months of the year. Utqiagvik in Alaska gets roughly eighty days of unbroken daylight, Tromsø holds its midnight sun close to two months — each paid back with a winter when the sun never clears the horizon.

Three families of solution turn up in the discussion. Borrow the times of the nearest latitude where the sun still rises and sets. Borrow Jerusalem's. Or divide the civil day at a fixed hour and keep a twenty-four hour Sabbath by the clock. Each costs something: the first is arbitrary about which latitude, the second severs the day from the sky overhead, the third drops sunset altogether. The responsa are genuinely unsettled, northern communities follow their own ruling, and no article can hand you a verdict the sources have not reached.

06The one thing here that doesn't move

Everything above moves. Friday's sunset is a minute off last Friday's, the clock label shifts twice a year, your friend two hundred miles west gets a different figure. Read far enough and nothing about the seventh day looks fixed. One thing is, and it is the day itself.

The 364-day year Day 4 keeps divides without remainder: 364 ÷ 7 = 52 exactly. Four seasons of 91 days, counted straight through, no month lengths absorbing a drift. So the Sabbath falls on the same year-days every year — day 4, then 11, 18, on to 361. The year is pinned each spring to the March equinox, read from a canonical per-year table rather than computed, because the equinox does not land on a fixed date. After day 364 the counting stops for one or two uncounted days, the Waiting Space, which the sacred week does not run through. So the year-days repeat forever while the ordinary dates they fall on do not.

One honesty note. That scheme reaches us because Enoch's Astronomical Book, Jubilees and the Dead Sea Scrolls carried it, and whether the Temple itself ever ran on it is still genuinely open. Day 4 keeps the reckoning without claiming to have closed the argument.

07Common questions