BOS to SEA: which side of the plane should you sit on?
Boston (BOS) to Seattle (SEA) is a 4,006 km (2,489 mi), roughly 5h 13m westbound flight. Here is where the sun sits along that path, computed with the same astronomy as our live calculator.
On most daytime BOS to SEA departures the sun favors the left side — sit on the right (a window on the right) for shade.
Sun side by season and departure time
| Season | Morning (8 am) | Midday (1 pm) | Evening (6 pm) |
|---|---|---|---|
| March equinox | Left | Left | Left |
| June solstice | Both | Left | Right |
| September equinox | Left | Left | Left |
| December solstice | Left | Left | Night |
What you’ll see on this flight
Views are a wash, so pick the right side if you want the cooler seat.
This westbound trip gives you a little of both sides. Views are basically even, so the right side wins on shade.
Takeoff
After takeoff from BOS, depending on the runway in use, Boston can sit almost under you on the left. Lake Chaubunagungamaug and Worcester also slide by on that side early in climb, while Massachusetts Bay is off to the right.
En route
- 18m in← LeftCatskill Mountains
About 20 minutes in, the Catskill Mountains are on the left. You see a long, low mountain block, not a sharp peak.
- 23m inRight →Adirondack Mountains
A few minutes later, the Adirondack Mountains are on the right. They stay off to that side as a broad wooded range.
- 50m in← LeftNiagara Falls
Around 50 minutes in, Niagara Falls is on the left. It is a quick side view, with the water split into separate falls near the border.
- 1h 16m in← LeftLake Huron
By about an hour and 15 minutes, Lake Huron is on the left. It reads as a huge sheet of water stretching past the window.
- 4h 23m inRight →Glacier National Park
Near the 4-and-a-half-hour mark, Glacier National Park is on the right. Waterton Lakes National Park sits there too, so that side gets the long look.
Landing
On descent, depending on the runway in use, the Cascade Range and Mount Rainier come in on the left. Near touchdown, Lake Washington is to the right, while Seattle is on the right and Tacoma on the left.
Sides and timings are computed from this route’s geometry. What you actually see depends on weather, air-traffic routing, and the runway in use on the day.
Frequently asked
Which side of the plane avoids the sun from BOS to SEA?
Across typical daytime departures, the sun predominantly hits the left side of the aircraft, so the right side stays shadier. Seat letters start at the left window, so choose the highest window letter (F on narrowbodies, K on many widebodies).
Which side has the sunset views on BOS to SEA flights?
For sunrise or sunset views, sit on the side the table marks as the sun side for your departure time — that is where the light is.
How long is the flight from BOS to SEA?
The great-circle distance is 4,006 km (2,489 mi), which works out to roughly 5h 13m in the air on this westbound routing. Winds and routing move the real block time around that estimate.
Does the date or departure time change the answer?
Yes — that is why the table shows both. The sun's path shifts with the season, and a morning departure can put the glare on the opposite side compared to an evening one. For a specific flight, the calculator samples the sun along the whole route for your exact date and time.
Which side should I sit on from BOS to SEA?
The route is balanced for views, so the shade call matters more. Sit on the right for the cooler side.
What will I see on this BOS to SEA flight?
You get early sights near Boston, then a mix of Great Lakes, western mountains, and a strong final look at the Cascade Range and Mount Rainier.