Denver (DEN) to Boston (BOS): On-Time Performance
Data through July 2026
The calendar drives reliability on DEN–BOS. December 2025 flights landed on schedule 86% of the time, but September 2025 dropped to 51% — a gap of 34 points. Across the full period the route averages 72% on-time against a national 78%. Morning departures also hold up better than evening ones (79% vs 70%), which matters most in the rough months.
- On-time
- 72%
- arrived <15 min late
- Avg delay
- 20 min
- completed flights
- Cancelled
- 1.0%
- Flights/day
- 11
- last 12 months
- Duration
- 3h 57m
- scheduled
- Distance
- 1,754 mi
Best airline from DEN to BOS
4 airlines flew this route regularly between 2024-07 and 2026-07.
| Airline | On-time | Avg delay | Cancelled | Flights |
|---|---|---|---|---|
| United Airlinesmost reliable | 77% | 16 min | 0.7% | 4,114 |
| Delta Air Lines | 75% | 16 min | 1.8% | 849 |
| JetBlue Airways | 67% | 30 min | 1.9% | 1,412 |
| Southwest Airlines | 64% | 24 min | 0.6% | 1,885 |
Monthly on-time trend
Best time to fly from DEN to BOS
Aim for departures around 7 a.m. (91% on-time); avoid 6 p.m. departures (50%).
By day of week
| Day | On-time | Avg delay |
|---|---|---|
| Monday | 71% | 22 min |
| Tuesday | 72% | 22 min |
| Wednesday | 73% | 19 min |
| Thursday | 69% | 24 min |
| Friday | 71% | 22 min |
| Saturdaybest | 79% | 13 min |
| Sunday | 72% | 19 min |
What causes delays on this route
Share of total delay minutes by cause, as reported by carriers to the US DOT.
- Late-arriving aircraft37%
- Airline operations25%
- National airspace system36%
- Weather2%
Frequently asked questions
- How often are flights from DEN to BOS delayed?
- 28% of DEN–BOS 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 20 minutes.
- Which airline is most reliable from DEN to BOS?
- United Airlines has the best on-time record on this route at 77%, based on 4,114 flights. 4 airlines flew DEN–BOS frequently enough to compare in this period.
- What is the best time of day to fly from DEN to BOS?
- Departures around 7 a.m. have the best record (91% on-time), while departures around 6 p.m. have the worst (50%). As on most US routes, delays accumulate through the day, so earlier flights are generally safer.
- How long is the flight from DEN to BOS?
- The scheduled DEN–BOS flight time averages 3h 57m over 1,754 miles. Actual arrival times vary — flights on this route land 15+ minutes late 28% of the time.
- How often are DEN to BOS 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 DEN to BOS?
- September 2025 was the roughest month in this dataset, with only 51% of arrivals on time. The best was December 2025 at 86%. If your dates are flexible, that 34-point gap is worth planning around.
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Based on 8,260 flights, 2024-07–2026-07. Source: US DOT Bureau of Transportation Statistics. Updated 2026-09-28.