Boston (BOS) to Washington (IAD): On-Time Performance
Data through July 2026
When you fly BOS to IAD matters as much as anything else about the booking: the route swung from 93% on-time in September 2024 to just 71% in July 2025. Across the full period the route averages 83% on-time against a national 78%. Morning departures also hold up better than evening ones (93% vs 71%), which matters most in the rough months.
- On-time
- 83%
- arrived <15 min late
- Avg delay
- 14 min
- completed flights
- Cancelled
- 1.7%
- Flights/day
- 4.2
- last 12 months
- Duration
- 1h 44m
- scheduled
- Distance
- 412 mi
Best airline from BOS to IAD
2 airlines flew this route regularly between 2024-07 and 2026-07.
| Airline | On-time | Avg delay | Cancelled | Flights |
|---|---|---|---|---|
| United Airlinesmost reliable | 83% | 13 min | 1.5% | 3,125 |
| Republic Airways | 79% | 32 min | 12.1% | 66 |
Monthly on-time trend
Best time to fly from BOS to IAD
Aim for departures around 1 p.m. (97% on-time); avoid 7 p.m. departures (71%).
By day of week
| Day | On-time | Avg delay |
|---|---|---|
| Monday | 84% | 10 min |
| Tuesday | 85% | 16 min |
| Wednesday | 82% | 14 min |
| Thursday | 79% | 17 min |
| Friday | 81% | 14 min |
| Saturdaybest | 87% | 9 min |
| Sunday | 82% | 15 min |
What causes delays on this route
Share of total delay minutes by cause, as reported by carriers to the US DOT.
- Late-arriving aircraft39%
- Airline operations22%
- National airspace system36%
- Weather3%
Frequently asked questions
- How often are flights from BOS to IAD delayed?
- 17% of BOS–IAD 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 14 minutes.
- Which airline is most reliable from BOS to IAD?
- United Airlines has the best on-time record on this route at 83%, based on 3,125 flights. 2 airlines flew BOS–IAD frequently enough to compare in this period.
- What is the best time of day to fly from BOS to IAD?
- Departures around 1 p.m. have the best record (97% on-time), while departures around 7 p.m. have the worst (71%). As on most US routes, delays accumulate through the day, so earlier flights are generally safer.
- How long is the flight from BOS to IAD?
- The scheduled BOS–IAD flight time averages 1h 44m over 412 miles. Actual arrival times vary — flights on this route land 15+ minutes late 17% of the time.
- How often are BOS to IAD flights cancelled?
- 1.7% of scheduled flights on this route were cancelled between 2024-07 and 2026-07, slightly above the national rate of 1.6%.
- What is the worst month to fly from BOS to IAD?
- July 2025 was the roughest month in this dataset, with only 71% of arrivals on time. The best was September 2024 at 93%. If your dates are flexible, that 22-point gap is worth planning around.
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Based on 3,191 flights, 2024-07–2026-07. Source: US DOT Bureau of Transportation Statistics. Updated 2026-09-28.