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

Washington, DC (IAD) to Denver, CO (DEN) flight delay odds

80.6% of 3,560 official scheduled IAD-to-DEN flights arrived on time; 10.8% arrived at least 30 minutes late and 0.6% 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 SIGNALLower disruption
80.6%arrived on time
10.8%30+ min late
0.6%cancelled
3,560scheduled flights
Based on July 2025–June 2026; on time means arrival less than 15 minutes late.
60+ minutes late6.1%all scheduled flights
120+ minutes late2.5%all scheduled flights
Diverted0.7%did not reach as scheduled
Average arrival+3.7 mincompleted flights

Which departure time was most reliable for IAD to DEN?

Among qualifying IAD-to-DEN departure window results, Late morning had the highest on-time rate: 90.6% of 394 flights. Evening was lowest at 65.7% across 797 flights.

Departure windowFlightsOn time30+ minCancelled
Early morning77687.8%5.3%0.5%
Late morning39490.6%4.8%0.8%
Afternoon1,25282.0%10.2%0.4%
Evening79765.7%20.1%1.1%
Night34182.7%10.9%0.3%

Which weekday was most reliable for IAD to DEN?

Among qualifying IAD-to-DEN weekday results, Saturday had the highest on-time rate: 83.3% of 478 flights. Thursday was lowest at 76.2% across 521 flights.

DayFlightsOn time30+ minCancelled
Monday52082.3%10.2%0.4%
Tuesday50383.1%10.1%0.2%
Wednesday50880.9%10.2%0.6%
Thursday52176.2%13.8%0.4%
Friday52379.5%11.1%0.6%
Saturday47883.3%9.0%0.4%
Sunday50779.5%11.0%1.8%

Which airline was most reliable for IAD to DEN?

Among qualifying IAD-to-DEN airline results, United Airlines had the highest on-time rate: 82.1% of 2,798 flights. Southwest Airlines was lowest at 75.2% across 762 flights.

AirlineFlightsOn time30+ minCancelled
United Airlines2,79882.1%10.2%0.5%
Southwest Airlines76275.2%13.3%1.2%

Which month was most reliable for IAD to DEN?

Among qualifying IAD-to-DEN month results, November 2025 had the highest on-time rate: 90.9% of 276 flights. July 2025 was lowest at 65.7% across 361 flights.

MonthFlightsOn time30+ minCancelled
July 202536165.7%22.2%1.4%
August 202533574.6%15.5%0.3%
September 202529484.7%7.8%0.0%
October 202528383.7%6.7%0.0%
November 202527690.9%3.3%0.4%
December 202530476.3%13.2%0.3%
January 202628083.6%8.2%3.9%
February 202625782.1%9.7%0.4%
March 202630080.0%13.0%0.7%
April 202629187.3%6.9%0.0%
May 202631684.2%7.9%0.0%
June 202626379.8%11.4%0.0%

What drove IAD to DEN delay minutes?

Late aircraft was the largest recorded IAD-to-DEN delay category, accounting for 36.0% of 42,398 BTS-attributed delay minutes during July 2025–June 2026.

Airline26.4%
Late aircraft36.0%
National airspace29.8%
Weather7.7%
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.