UA2040 BostonBOS · 17:01 San FranciscoSFO · 19:00
UA2040 by United Airlines flies from Boston (BOS) to San Francisco (SFO) for the Sun, Sep 6 departure.
Same number through BOS → ORD → SFO
departs BOS · on schedule
board checked 14m ago · checking again in 45s
The route today
live boardsWeather lens
Delay & cancellation outlook for this flight
Measured, 90-day sampleConditions at BOS and SFO are near their clear-air norm right now, so this reflects the route's recent baseline rather than a weather penalty. For this route and airline, under conditions like today's, over the last 90 days.
Pro Flight Search tracking, 90 days · the weather × delay correlation study → · live weather risk by airport →
When it flies
scheduled departuresEach mark is a scheduled departure at its origin-local time. Today is highlighted.
Other Boston to San Francisco flights today
same route · United AirlinesIf UA2040 is cancelled, these are the other United Airlines nonstop flights from Boston to San Francisco on the same day, with scheduled departure times in BOS local time. Most flights posting a delay still operate — rebooking usually only beats a very large posted delay. Every airline on this route →
How UA2040 actually runs
Pro Flight Search has tracked every published board update for UA2040 across the BOS and SFO boards: schedule changes, gate pushes and actual clocks. Early read — pattern not clear yet. Only 2 completed legs so far: landed +13 min. Not enough to call it.
The verdict above is that record speaking, so it reflects how UA2040 operates rather than what the timetable promises. Numbers refresh as new flights operate.
How this operation is measured
Board log
scheduled → actual, per operationBoard clocks recorded as BOS and SFO published them.
Planning around UA2040? Will a delayed flight be cancelled? · Do planes make up time in the air? · How we measure
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Pro Flight Search — UA2040 Boston to San Francisco on-time performance, measured from the BOS and SFO airport boards.
https://proflightsearch.com/flight/UA2040
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