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

Boston, MA (BOS) to Chicago, IL (ORD) flight delay odds

70.3% of 7,637 official scheduled BOS-to-ORD flights arrived on time; 19.0% arrived at least 30 minutes late and 2.9% 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
70.3%arrived on time
19.0%30+ min late
2.9%cancelled
7,637scheduled flights
Based on July 2025–June 2026; on time means arrival less than 15 minutes late.
60+ minutes late11.6%all scheduled flights
120+ minutes late5.4%all scheduled flights
Diverted0.5%did not reach as scheduled
Average arrival+14.2 mincompleted flights

Which departure time was most reliable for BOS to ORD?

Among qualifying BOS-to-ORD departure window results, Early morning had the highest on-time rate: 85.6% of 2,107 flights. Evening was lowest at 49.4% across 1,597 flights.

Departure windowFlightsOn time30+ minCancelled
Early morning2,10785.6%6.6%2.2%
Late morning1,25079.8%12.5%2.3%
Afternoon2,68166.2%22.1%2.9%
Evening1,59749.4%35.1%4.3%

Which weekday was most reliable for BOS to ORD?

Among qualifying BOS-to-ORD weekday results, Tuesday had the highest on-time rate: 74.9% of 1,069 flights. Sunday was lowest at 65.2% across 1,160 flights.

DayFlightsOn time30+ minCancelled
Monday1,17166.8%21.3%5.6%
Tuesday1,06974.9%15.6%2.7%
Wednesday1,03673.9%16.9%1.9%
Thursday1,14369.9%18.4%2.6%
Friday1,15270.4%17.8%2.1%
Saturday90671.7%19.1%1.4%
Sunday1,16065.2%23.2%3.4%

Which airline was most reliable for BOS to ORD?

Among qualifying BOS-to-ORD airline results, United Airlines had the highest on-time rate: 73.3% of 2,678 flights. Delta Air Lines was lowest at 62.8% across 962 flights.

AirlineFlightsOn time30+ minCancelled
United Airlines2,67873.3%16.5%1.9%
American Airlines2,12570.8%19.0%2.8%
Delta Air Lines96262.8%24.7%3.1%
Republic Airways89466.0%20.9%5.9%
JetBlue Airways53371.7%17.8%2.3%
Envoy Air44572.4%18.9%3.6%

Which month was most reliable for BOS to ORD?

Among qualifying BOS-to-ORD month results, May 2026 had the highest on-time rate: 78.0% of 738 flights. October 2025 was lowest at 63.3% across 695 flights.

MonthFlightsOn time30+ minCancelled
July 202567366.3%23.3%3.3%
August 202568371.7%18.7%2.2%
September 202566067.4%22.4%0.6%
October 202569563.3%25.6%0.9%
November 202564268.5%21.3%4.5%
December 202555669.2%22.5%0.7%
January 202650065.6%16.8%6.2%
February 202650277.3%9.8%7.2%
March 202659765.7%18.6%6.4%
April 202664174.6%15.0%2.2%
May 202673878.0%14.2%0.3%
June 202675074.3%17.5%2.8%

What drove BOS to ORD delay minutes?

Late aircraft was the largest recorded BOS-to-ORD delay category, accounting for 40.2% of 168,736 BTS-attributed delay minutes during July 2025–June 2026.

Airline20.1%
Late aircraft40.2%
National airspace36.2%
Weather3.3%
Security0.1%
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.