Boston (BOS) to Denver (DEN): On-Time Performance
Data through July 2026
Boston (BOS) to Denver (DEN) effectively runs on two schedules. In March 2025, 89% of arrivals were on time; in February 2025 that fell to 62% — a 27-point seasonal swing. Across the full period the route averages 77% on-time against a national 78%. Morning departures also hold up better than evening ones (87% vs 56%), which matters most in the rough months.
- On-time
- 77%
- arrived <15 min late
- Avg delay
- 15 min
- completed flights
- Cancelled
- 1.0%
- Flights/day
- 11
- last 12 months
- Duration
- 4h 42m
- scheduled
- Distance
- 1,754 mi
Best airline from BOS to DEN
4 airlines flew this route regularly between 2024-07 and 2026-07.
| Airline | On-time | Avg delay | Cancelled | Flights |
|---|---|---|---|---|
| United Airlinesmost reliable | 82% | 12 min | 0.8% | 4,111 |
| Delta Air Lines | 77% | 12 min | 1.8% | 849 |
| JetBlue Airways | 72% | 19 min | 1.6% | 1,411 |
| Southwest Airlines | 71% | 18 min | 0.6% | 1,937 |
Monthly on-time trend
Best time to fly from BOS to DEN
Aim for departures around 6 a.m. (90% on-time); avoid 5 p.m. departures (42%).
By day of week
| Day | On-time | Avg delay |
|---|---|---|
| Monday | 79% | 15 min |
| Tuesday | 79% | 14 min |
| Wednesdaybest | 80% | 11 min |
| Thursday | 75% | 17 min |
| Friday | 74% | 19 min |
| Saturday | 78% | 13 min |
| Sunday | 76% | 14 min |
What causes delays on this route
Share of total delay minutes by cause, as reported by carriers to the US DOT.
- Late-arriving aircraft43%
- Airline operations27%
- National airspace system27%
- Weather3%
Frequently asked questions
- How often are flights from BOS to DEN delayed?
- 23% of BOS–DEN flights arrived 15 or more minutes late (the US DOT definition of a delay) between 2024-07 and 2026-07. The average arrival delay across completed flights was 15 minutes.
- Which airline is most reliable from BOS to DEN?
- United Airlines has the best on-time record on this route at 82%, based on 4,111 flights. 4 airlines flew BOS–DEN frequently enough to compare in this period.
- What is the best time of day to fly from BOS to DEN?
- Departures around 6 a.m. have the best record (90% on-time), while departures around 5 p.m. have the worst (42%). As on most US routes, delays accumulate through the day, so earlier flights are generally safer.
- How long is the flight from BOS to DEN?
- The scheduled BOS–DEN flight time averages 4h 42m over 1,754 miles. Actual arrival times vary — flights on this route land 15+ minutes late 23% of the time.
- How often are BOS to DEN flights cancelled?
- 1% of scheduled flights on this route were cancelled between 2024-07 and 2026-07, at or below the national rate of 1.6%.
- What is the worst month to fly from BOS to DEN?
- February 2025 was the roughest month in this dataset, with only 62% of arrivals on time. The best was March 2025 at 89%. If your dates are flexible, that 27-point gap is worth planning around.
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Based on 8,308 flights, 2024-07–2026-07. Source: US DOT Bureau of Transportation Statistics. Updated 2026-09-28.