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

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

75.7% of 4,674 official scheduled SFO-to-BOS flights arrived on time; 15.5% arrived at least 30 minutes late and 1.3% 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
75.7%arrived on time
15.5%30+ min late
1.3%cancelled
4,674scheduled flights
Based on July 2025–June 2026; on time means arrival less than 15 minutes late.
60+ minutes late9.1%all scheduled flights
120+ minutes late3.6%all scheduled flights
Diverted0.1%did not reach as scheduled
Average arrival+6.5 mincompleted flights

Which departure time was most reliable for SFO to BOS?

Among qualifying SFO-to-BOS departure window results, Early morning had the highest on-time rate: 83.5% of 1,396 flights. Late morning was lowest at 64.3% across 633 flights.

Departure windowFlightsOn time30+ minCancelled
Early morning1,39683.5%10.3%1.0%
Late morning63364.3%25.8%0.6%
Afternoon1,43572.6%17.4%2.0%
Evening15580.0%14.8%2.6%
Night1,05575.9%13.8%1.2%

Which weekday was most reliable for SFO to BOS?

Among qualifying SFO-to-BOS weekday results, Saturday had the highest on-time rate: 83.6% of 550 flights. Thursday was lowest at 70.1% across 698 flights.

DayFlightsOn time30+ minCancelled
Monday71072.1%18.0%2.5%
Tuesday66478.0%14.9%1.1%
Wednesday64877.0%15.4%0.2%
Thursday69870.1%20.6%0.3%
Friday70576.6%15.9%0.7%
Saturday55083.6%9.8%0.7%
Sunday69974.7%12.7%3.7%

Which airline was most reliable for SFO to BOS?

Among qualifying SFO-to-BOS airline results, United Airlines had the highest on-time rate: 78.1% of 1,866 flights. Delta Air Lines was lowest at 73.7% across 899 flights.

AirlineFlightsOn time30+ minCancelled
United Airlines1,86678.1%14.8%1.0%
JetBlue Airways1,67474.0%17.3%1.8%
Delta Air Lines89973.7%14.9%1.4%
Alaska Airlines23476.9%10.3%0.4%
Southwest Airlines10.0%100.0%0.0%

Which month was most reliable for SFO to BOS?

Among qualifying SFO-to-BOS month results, August 2025 had the highest on-time rate: 84.5% of 431 flights. June 2026 was lowest at 68.3% across 502 flights.

MonthFlightsOn time30+ minCancelled
July 202545075.8%15.8%0.2%
August 202543184.5%7.7%0.2%
September 202540872.1%21.1%0.0%
October 202542870.1%22.9%0.7%
November 202536076.1%14.7%2.8%
December 202535681.2%12.9%0.6%
January 202631377.3%14.1%5.4%
February 202628377.7%9.5%8.1%
March 202632377.7%17.0%0.3%
April 202638176.4%15.5%0.3%
May 202643975.4%14.4%0.0%
June 202650268.3%18.1%0.8%

What drove SFO to BOS delay minutes?

National airspace was the largest recorded SFO-to-BOS delay category, accounting for 38.6% of 78,166 BTS-attributed delay minutes during July 2025–June 2026.

Airline22.3%
Late aircraft36.6%
National airspace38.6%
Weather2.6%
Security0.0%
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.