Which side to sit on: sun and view, train, bus, plane or ferry

Say where you leave from, where you are going, when you leave and how — train, bus, car, plane or ferry — and the tool tells you which side the sun will be on for the whole trip, which side to sit on for shade, and, if there is something you hope to see on the way, which window it will be behind. Free, no account, nothing stored.

What it does, and why it is here

Every scenic line has the question, and the forums are full of it: which side of the train to sit on from Oslo to Bergen, which side of the plane sees Mount Fuji from Singapore, which side of the Staten Island ferry faces the Statue of Liberty. The answers people give each other are right for the day they travelled and the hour they left, and silently wrong for yours: the sun does not sit still, and a morning departure and an afternoon one put it in opposite windows.

The tool computes it for your departure. It draws the way from the first place to the second as the straight arc a plane would fly, samples it every few minutes, works out which way the vehicle is pointing at each sample and where the sun stands from there — the same ephemeris the golden hour and moon tools here run on — and adds up the minutes the sun spends in the left window, in the right one, straight ahead and behind. The side with fewer of those minutes is the shady one, and that is the seat it recommends.

The view is the other half, and the half nobody computes. Name a mountain, a monument or a town, and the answer says which window it is behind at the moment the way passes closest to it, how far off it is then, and the bearing to point your camera at.

What you fill in

• From and To — the two cities. Picking each from the list fills in its coordinates and its time zone; a name typed by hand designates nothing.
• Departure — the date and time on the departure place’s clock, as the ticket prints it. Left empty, it means the next full hour.
• How you travel — train, bus, car, plane or ferry. It decides how long the trip takes when you do not say so yourself.
• Trip length (optional) — in minutes, what the ticket says. It always beats the estimate.
• Passes through (optional) — a station or town the line visibly goes through. A railway that hugs a coast or skirts a range is not a straight arc; naming the place it bends through turns one arc into two and puts the landmark in the right window. The Tokaido line from Tokyo to Kyoto runs south of Fuji, through Shizuoka: without that stop, the straight line would pass north of the mountain and get the side wrong.
• Something to see on the way (optional) — the landmark. A mountain, a bridge, a city skyline.

What you get back

The seat, first: sit on the left for shade, or either side will do when the sun spends as long in each window, or a night trip when it is down the whole way. Under it, the departure and arrival times — the arrival written on the arrival place’s clock when the trip crosses a time zone — the length and the distance, and the heading at departure and on arrival.

Then the card: the same line over the vehicle seen from above, the sun drawn where a passenger would have it, the lit windows on one flank and the shaded ones on the other, and a pin for the landmark. It is made to be sent to whoever is booking the seats.

Then the view, when you asked for one, and the sun’s account: how long in each window, the minute it changes sides, and any sunrise or sunset seen on the way. Last, the way itself as a table — time, heading, where the sun is and how high — for whoever wants to check the reasoning, and to download as a spreadsheet. The trip can also be added to a calendar, with the advice as its title.

How to read it, and where it stops

The way is a great circle, and that is exactly right for a plane, fair for a coach on a motorway, and an approximation for anything that follows a valley. The tool is honest about it: the headings it used are in the table, and the passes through field is how you tell it where the line really goes. It knows nothing of tunnels, of which side the platform is on, or of the seat numbering of a given operator — only where the light comes from.

“Left” and “right” are the passenger’s, facing forward. Within ten degrees of the nose or the tail the sun lights neither flank, and the answer counts those minutes apart, as ahead and behind.

A trip longer than a day is refused: split it at the connection, which is where you would swap seats anyway.

Nothing is stored

The two cities, the time and the landmark are read from your request, used for the computation and dropped. The address of the answer carries them, so you can send it to someone, and it recomputes from scratch when they open it. No account, no cookie, no tracking of where you are going.

Questions

Which side of the train should I sit on for the view?

Name what you hope to see in the something to see on the way box, and the answer says which window it will be behind, how far off it is when the way passes closest, and the bearing to point a camera at. Left empty, the tool answers for the sun instead, which is the other half of the same question.

Does it know the real railway line, or the actual flight path?

No, and the answer says so. It draws the great circle between your two places: exactly right for a plane, fair for a coach on a motorway, an approximation for anything that follows a valley or hugs a coast. Where the real line bends, name a town or a station it visibly passes through and the arc bends with it — that single field is the difference between the right window and the wrong one on a line like Tokyo to Kyoto, which runs south of Mount Fuji rather than straight at it.

How does it work out how long the trip takes?

From the distance and the way you travel, when you do not say. These are the cruise speeds it falls back on, and they are meant to be read as “about” rather than as a timetable.

What the ticket says always beats the estimate: put it in the trip length box and the whole computation follows it instead.

Left and right of what?

Of a passenger facing forward. When the sun comes within ten degrees of the nose or the tail it lights neither flank, and those minutes are counted separately — as ahead and behind — rather than being credited to a side that does not really have them.

What does “either side will do” mean?

That the sun spends about as long in one window as in the other across the whole trip, usually because the way turns through a wide angle or because the sun crosses the nose along it. The minute it changes sides is in the answer, so you can still choose for the half of the journey you care about.

What happens if I travel at night?

The answer says so and stops recommending a seat: with the sun down the whole way, no side is the shady one. Any sunrise or sunset falling inside the trip is named, with its time.

How long a trip can it take?

Up to twenty-four hours. Past that it refuses, because a longer journey is two journeys with a connection in the middle — and the connection is where you would change seats anyway.

Can I keep the answer, or send it on?

Three ways. The card is a picture of the vehicle from above with the sun and the lit windows drawn on it, made to be sent to whoever is booking. The way itself, heading by heading, downloads as a spreadsheet. And the trip can be added to a calendar, with the advice as its title.

Is anything about my trip stored?

No. The two places, the departure, the trip length and the landmark are read from the request, used, and dropped. They travel in the address of the answer so that the link can be shared and recomputed, and that address is the only place they exist.

Sources and further reading

• Great-circle distance and bearing formulas, the geometry the way and its headings are built on.
• NOAA Solar Calculator, to check where the sun stands at any point of the way.
• GeoNames, the geographical database the place boxes resolve against.