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

San Juan, PR (SJU) to Boston, MA (BOS) flight delay odds

69.6% of 2,001 official scheduled SJU-to-BOS flights arrived on time; 18.7% arrived at least 30 minutes late and 2.7% 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 SIGNALVariable
69.6%arrived on time
18.7%30+ min late
2.7%cancelled
2,001scheduled flights
Based on July 2025–June 2026; on time means arrival less than 15 minutes late.
60+ minutes late10.5%all scheduled flights
120+ minutes late4.1%all scheduled flights
Diverted0.3%did not reach as scheduled
Average arrival+12.2 mincompleted flights

Which departure time was most reliable for SJU to BOS?

Among qualifying SJU-to-BOS departure window results, Early morning had the highest on-time rate: 78.6% of 420 flights. Evening was lowest at 58.3% across 350 flights.

Departure windowFlightsOn time30+ minCancelled
Early morning42078.6%10.2%1.9%
Late morning14976.5%16.1%4.0%
Afternoon1,01168.6%19.7%2.4%
Evening35058.3%27.4%4.6%
Night7171.8%16.9%1.4%

Which weekday was most reliable for SJU to BOS?

Among qualifying SJU-to-BOS weekday results, Tuesday had the highest on-time rate: 77.1% of 262 flights. Sunday was lowest at 63.9% across 299 flights.

DayFlightsOn time30+ minCancelled
Monday28767.2%19.5%4.9%
Tuesday26277.1%11.8%1.1%
Wednesday24571.0%15.1%1.2%
Thursday29567.5%21.7%0.7%
Friday28474.3%17.3%1.1%
Saturday32967.8%20.7%4.3%
Sunday29963.9%23.1%5.4%

Which airline was most reliable for SJU to BOS?

Among qualifying SJU-to-BOS airline results, Delta Air Lines had the highest on-time rate: 76.6% of 398 flights. Frontier Airlines was lowest at 67.6% across 34 flights.

AirlineFlightsOn time30+ minCancelled
JetBlue Airways1,41567.7%20.7%3.0%
Delta Air Lines39876.6%12.3%1.5%
Spirit Airlines15469.5%16.9%3.9%
Frontier Airlines3467.6%17.6%2.9%

Which month was most reliable for SJU to BOS?

Among qualifying SJU-to-BOS month results, May 2026 had the highest on-time rate: 82.1% of 145 flights. January 2026 was lowest at 56.5% across 207 flights.

MonthFlightsOn time30+ minCancelled
July 202517972.6%18.4%2.8%
August 202518664.5%24.7%1.1%
September 20258475.0%13.1%0.0%
October 20259873.5%17.3%1.0%
November 202512074.2%13.3%1.7%
December 202518966.1%23.8%1.6%
January 202620756.5%22.2%11.1%
February 202620761.4%22.7%7.2%
March 202623574.0%16.2%1.7%
April 202621569.8%18.1%0.0%
May 202614582.1%13.1%0.0%
June 202613678.7%12.5%0.0%

What drove SJU to BOS delay minutes?

Late aircraft was the largest recorded SJU-to-BOS delay category, accounting for 47.2% of 39,314 BTS-attributed delay minutes during July 2025–June 2026.

Airline32.2%
Late aircraft47.2%
National airspace19.2%
Weather1.4%
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.