Route on-time record
IAD to BOS: most on-time flights and the best time to fly
Dulles (Washington Dulles International Airport) to Boston (Boston Logan International Airport). 1,487 nonstop flights in Jun 2025 to May 2026, 75% arrived within 15 minutes and 1.7% were cancelled. The most reliable flight number was United 641 at 8:22 AM.
Flying on a specific date? We’ll adjust for the month, the weekday and the forecast.
IAD → BOS
Dulles to Boston: 1,487 nonstop flights a year
On time (12 months)
75%
Cancelled
1.7%
avg delay 20 min
Best time to leave
Before 9 AM
91% on time vs 57% 3 to 6 PM
Most reliable airline
United
74% chance on time
Lowest nonstop fare seen in the next two months: $71 (United 755 on 2026-11-11). Fares open on our travel partner (Aviasales). Pick the flight number you chose here.
Most reliable nonstop flights
Ranked by the chance the flight operates and arrives within 15 minutes of schedule, from Jun 2025 to May 2026 records.
#1 · United 641
8:22 AM → 10:04 AM1h 42m nonstop
Local times, typical schedule. Last flown 2026-05-31.
89%
chance on time
- On time (history)
- 91%
- Cancelled
- 1.2%
- Avg arrival delay
- 6 min
- Arrived on time 91% of the time (340 flights, Jun 2025 to May 2026).
- Leaves in this route's most on-time window (Before 9 AM: 91% on time; 3 to 6 PM: 57%).
- Departs outside IAD's trouble window (1 PM to 7 PM, when 75% of its 63 ground stops and delay programs started).
Strong track record · 340 flights
Find United 641 fares Opens this date on Aviasales#2 · United 1392
12:55 PM → 2:42 PM1h 43m nonstop
Local times, typical schedule. Last flown 2026-05-31.
79%
chance on time
- On time (history)
- 83%
- Cancelled
- 0.0%
- Avg arrival delay
- 9 min
- Arrived on time 83% of the time (88 flights, Jun 2025 to May 2026).
- Never cancelled in 88 scheduled flights.
- Departs outside IAD's trouble window (1 PM to 7 PM, when 75% of its 63 ground stops and delay programs started).
- Lands inside BOS's trouble window: 79% of its 196 ground stops and delay programs started between noon and 6 PM.
Moderate track record · 88 flights
Find United 1392 fares Opens this date on Aviasales#3 · United 755
10:15 PM → 11:59 PM1h 44m nonstop
Local times, typical schedule. Last flown 2026-05-31.
76%
chance on time
- On time (history)
- 78%
- Cancelled
- 2.2%
- Avg arrival delay
- 15 min
- Arrived on time 78% of the time (318 flights, Jun 2025 to May 2026).
- Departs outside IAD's trouble window (1 PM to 7 PM, when 75% of its 63 ground stops and delay programs started).
Strong track record · 318 flights
Find United 755 fares Opens this date on Aviasales#4 · United 688
5:10 PM → 7:06 PM1h 54m nonstop
Local times, typical schedule. Last flown 2026-05-31.
58%
chance on time
- On time (history)
- 59%
- Cancelled
- 2.8%
- Avg arrival delay
- 38 min
- Arrived on time 59% of the time (352 flights, Jun 2025 to May 2026).
- Leaves in this route's least on-time window (3 to 6 PM: 57% on time; Before 9 AM: 91%).
- Departs inside IAD's trouble window: 75% of its 63 ground stops and delay programs started between 1 PM and 7 PM.
Strong track record · 352 flights
Find United 688 fares Opens this date on Aviasales
Airlines on this route
Season-adjusted chance of operating and arriving on time.
- United Airlines74%
1,484 flights · 76% on time as flown · 1.7% cancel
On time by departure time
All airlines, scheduled local departure, Jun 2025 to May 2026.
- Before 9 AM91%
233 flights · avg delay 5 min
- 9 AM to noon91%
111 flights · avg delay 7 min
- Noon to 3 PM79%
365 flights · avg delay 16 min
- 3 to 6 PM57%
422 flights · avg delay 38 min
- After 9 PM79%
356 flights · avg delay 14 min
Best day: Saturday (83%). Worst: Thursday (73%).
Smarter routing
Nearby airports that run more on time
BWI → MHT 81% chance on time
Baltimore/Washington International Thurgood Marshall Airport to Manchester-Boston Regional Airport · 1,710 flights a year · 90 mi from your airports · yours: 74%
BWI → PVD 77% chance on time
Baltimore/Washington International Thurgood Marshall Airport to Rhode Island T. F. Green International Airport · 1,882 flights a year · 94 mi from your airports · yours: 74%
On time by month
All airlines, Jun 2023 to May 2026. Several years per month, so one stormy season doesn't define a month. Travel-month estimates use this seasonal pattern.
What delays this route
- Air traffic control and airport volume51%
- Late-arriving aircraft23%
- Airline (crew, maintenance, boarding)19%
- Severe weather7%
Share of delay minutes by the cause airlines report to the US DOT.
Historical odds, not a guarantee. Built from the US DOT Bureau of Transportation Statistics on-time reports (Jun 2025 to May 2026), FAA ground stop and delay program advisories, and 20 years of airport weather observations. Covers US airlines that report to the DOT; schedules are flights operated recently, so confirm times when you book. ATIS Alerts is not affiliated with any airline. Fares are what Aviasales travelers saw in recent searches (USD, one way, 1 adult), not live quotes; the partner site shows the current price. Fare links go to our travel partner and may earn us a commission at no cost to you. Affiliate disclosure
IAD to BOS questions
- What time of day is best to fly IAD to BOS?
- Before 9 AM: 91% of flights arrived on time, against 57% for departures 3 to 6 PM. Later flights inherit delays from earlier ones, so the first departures of the day usually run best.
- Which airline is most on time from IAD to BOS?
- United, with a season-adjusted 74% chance of operating and arriving on time over 1,484 flights. The adjustment compares each airline with what the route did in the months it flew, so a carrier that skipped a stormy month gets no free credit.
- What is the worst month for delays on IAD to BOS?
- September (65% on time); the best was February (88%), averaged over Jun 2023 to May 2026.
- Is this a prediction for my flight?
- No. These are historical odds from the US DOT on-time reports, FAA advisories and airport weather records. Check your flight status and the FAA delay board on the day you fly.
More routes from IAD
- BOS to IAD (return)
- IAD to ATL 78%
- IAD to DEN 81%
- IAD to SFO 79%
- IAD to LAX 80%
- IAD to MCO 81%
- IAD to CLT 83%
- IAD to ORD 75%
- IAD to SEA 76%
- IAD to DFW 77%
- IAD to IAH 83%
- IAD to EWR 73%
- IAD to TPA 79%
Live status: FAA delays and ground stops