Boston to San Francisco: what the BOS to SFO corridor looks like
- Departure
- Boston Logan International Airport, Boston, the United States
- Arrival
- San Francisco International Airport, San Francisco, the United States
- Great-circle distance
- 4,341 km (2,344 nm)
- Typical airborne time
- 5h 33m
- Usual cruise levels
- FL340 to FL400
- Initial track
- westbound
Route overview
Boston Logan International Airport (BOS) in Boston, the United States, to San Francisco International Airport (SFO) in San Francisco, the United States, is a great-circle distance of 4,341 km, about 2,344 nautical miles. At typical jet cruise speeds, and with an allowance for climb, descent and approach, that works out to roughly 5h 33m of airborne time. The great-circle track leaves Boston westbound and spends most of the flight in subtropical air.
Leaving Boston
Boston Logan sits on reclaimed land in the harbour, so departures climb straight out over cold Atlantic water. The temperature difference between sea and land makes low level shear common here in spring. The great-circle track leaves BOS westbound, and the first waypoint band of the flight sits close to 41.2N 83.9W. On a sector of 5h 33m, the climb to cruise takes roughly the first twenty to twenty five minutes.
Mountain wave over the Rockies
The midpoint of the BOS to SFO track lies near 40.0N 96.7W, about 2,171 km from Boston, which is where the corridor spends its longest continuous stretch at cruise level. The track crosses the Rocky Mountains, where westerly wind lifted over the ridge line oscillates downwind and produces mountain wave turbulence at cruise level. On windy days that gives a defined bumpy segment of roughly twenty to thirty minutes, with settled air before and after it.
Cruise altitudes on this sector
Long haul crews normally start cruise around FL340, then step climb toward FL380 or FL400 as the aircraft burns off fuel and can hold a higher level. Choice of level matters because turbulence is layered: a change of two or three thousand feet often puts the aircraft into calmer air, and that is one of the first adjustments a crew will request.
Arriving into San Francisco
Approaches into San Francisco cross coastal terrain into the marine layer. The strong afternoon westerly through the gap is the local factor that makes late day arrivals livelier than morning ones. Descent normally begins around 38.8N 109.5W, roughly 1,085 km before SFO, and takes about half an hour from cruise level to touchdown.
Seasonal pattern
Mountain wave activity follows the strength of the winter westerlies, so the most defined wave segments occur between November and March, and mid summer crossings are typically calm.
Flying this route with less worry
Turbulence on this corridor is a comfort issue rather than a safety one. Airliners are certified to handle loads well beyond anything the atmosphere produces here, crews are trained for it, and the seat belt sign is the tool that keeps the cabin settled. What this page adds is knowing in advance: the map and Calmness Score above use current WAFS forecast data for BOS to SFO, so you can see what to expect before you board.