Best Time to Fly IAD to PWM: On-Time Stats by Hour & Airline
Washington Dulles International → Portland International Jetport
Data through July 2026 · Last updated October 18, 2026
Over the last 12 months, 88.5% of Washington (IAD) to Portland (PWM) flights arrived on time (787 scheduled flights). That is 10.8 points above the national average of 77.6%.
Republic Airways was the most punctual of the 2 airlines on the route at 90.0%, while United Airlines trailed at 72.9%.
April has been the best month (97% on time) and Thursday the weakest day of the week (84%).
1.9% of flights were cancelled, versus 1.8% nationally.
IAD to PWM on-time performance by airline
Last 12 months. Airlines with fewer than 30 completed flights are marked “limited data”.
| Airline | On time | Avg delay when late | Cancelled | Flights |
|---|---|---|---|---|
| Republic Airways | 90.0% | 72 min | 2.1% | 717 |
| United Airlines | 72.9% | 66 min | 0.0% | 70 |
80%+ good 70–79.9% fair <70% poor
Best time of day to fly IAD to PWM
On-time arrival % by scheduled departure hour (local time), 1,582 flights over 24 months.
Show the numbers
| Departure hour | On time | Cancelled | Flights |
|---|---|---|---|
| 8am–9am | 93.8% | 0.7% | 309 |
| 12pm–1pm | 89.7% | 1.9% | 464 |
| 1pm–2pm | 91.1% | 0.9% | 113 |
| 3pm–4pm | 79.2% | 0.0% | 53 |
| 5pm–6pm | 81.6% | 3.1% | 291 |
| 10pm–11pm | 78.5% | 3.7% | 352 |
Best day of the week
24 months, by day of departure.
Best month to fly
24 months, by calendar month.
Holiday travel on IAD to PWM
On-time arrivals during holiday periods compared with all other days, last 24 months.
| Period | On time | vs other days | Cancelled | Flights |
|---|---|---|---|---|
| Thanksgiving week (Tue before to Mon after) | Limited data | 25 | ||
| Christmas & New Year (Dec 20 - Jan 3) | 86.7% | -2.5 pts | 0.0% | 45 |
| Summer peak (Jun 15 - Aug 15) | 79.6% | -9.5 pts | 5.2% | 461 |
| All other days | 89.2% | — | 0.9% | 1,051 |
Monthly on-time trend
On-time arrival % each month, with the 12-month US average for reference.
What causes delays on this route
Share of reported delay minutes, last 12 months (BTS cause categories).