BTS DATA COMPLETE THROUGH JUNE 2026HISTORICAL ODDS · NOT LIVE FLIGHT STATUS
DelayOddsKnow the route before you book
BOS→SFO

Boston, MA (BOS) to San Francisco, CA (SFO) flight delay odds

71.5% of 4,676 official scheduled BOS-to-SFO flights arrived on time; 17.6% arrived at least 30 minutes late and 1.2% were cancelled during July 2025–June 2026.

Source: U.S. Bureau of Transportation Statistics · Reporting window: July 2025–June 2026 · Updated September 16, 2026

HISTORICAL ROUTE SIGNALGenerally reliable
71.5%arrived on time
17.6%30+ min late
1.2%cancelled
4,676scheduled flights
Based on July 2025–June 2026; on time means arrival less than 15 minutes late.
60+ minutes late9.3%all scheduled flights
120+ minutes late3.6%all scheduled flights
Diverted0.3%did not reach as scheduled
Average arrival+7.8 mincompleted flights

Which departure time was most reliable for BOS to SFO?

Among qualifying BOS-to-SFO departure window results, Early morning had the highest on-time rate: 82.4% of 1,492 flights. Evening was lowest at 60.1% across 1,476 flights.

Departure windowFlightsOn time30+ minCancelled
Early morning1,49282.4%8.2%1.5%
Late morning76477.0%14.5%0.8%
Afternoon84867.3%21.2%0.9%
Evening1,47660.1%26.8%1.4%
Night9669.8%16.7%0.0%

Which weekday was most reliable for BOS to SFO?

Among qualifying BOS-to-SFO weekday results, Tuesday had the highest on-time rate: 77.9% of 661 flights. Thursday was lowest at 67.0% across 697 flights.

DayFlightsOn time30+ minCancelled
Monday70767.8%19.4%3.3%
Tuesday66177.9%13.5%1.2%
Wednesday64874.5%15.6%0.5%
Thursday69767.0%21.8%0.7%
Friday71071.0%19.7%0.4%
Saturday55474.9%14.4%0.5%
Sunday69968.7%18.0%1.7%

Which airline was most reliable for BOS to SFO?

Among qualifying BOS-to-SFO airline results, United Airlines had the highest on-time rate: 75.3% of 1,867 flights. Alaska Airlines was lowest at 60.3% across 234 flights.

AirlineFlightsOn time30+ minCancelled
United Airlines1,86775.3%15.5%1.1%
JetBlue Airways1,67669.3%19.3%1.3%
Delta Air Lines89870.5%17.1%1.4%
Alaska Airlines23460.3%24.8%0.4%
Southwest Airlines1100.0%0.0%0.0%

Which month was most reliable for BOS to SFO?

Among qualifying BOS-to-SFO month results, August 2025 had the highest on-time rate: 84.2% of 431 flights. June 2026 was lowest at 55.8% across 502 flights.

MonthFlightsOn time30+ minCancelled
July 202545073.6%15.8%0.2%
August 202543184.2%9.0%0.2%
September 202540881.4%13.5%0.0%
October 202542974.6%17.2%0.7%
November 202536172.9%15.5%2.5%
December 202535763.6%21.0%0.8%
January 202631369.3%17.9%4.5%
February 202628269.1%15.2%7.1%
March 202632376.8%14.2%0.0%
April 202638169.6%18.1%0.3%
May 202643968.8%20.5%0.0%
June 202650255.8%30.1%1.0%

What drove BOS to SFO delay minutes?

National airspace was the largest recorded BOS-to-SFO delay category, accounting for 39.0% of 81,903 BTS-attributed delay minutes during July 2025–June 2026.

Airline22.8%
Late aircraft36.2%
National airspace39.0%
Weather1.8%
Security0.2%
This is historical evidence, not a forecast.

Weather, schedules and operations change. For a trip you have already booked, use the airline or airport for live status.