Best Time to Fly MIA to IAD: On-Time Stats by Hour & Airline
Miami International → Washington Dulles International
Data through July 2026 · Last updated October 18, 2026
Over the last 12 months, 83.1% of Miami (MIA) to Washington (IAD) flights arrived on time (625 scheduled flights). That is 5.4 points above the national average of 77.6%.
United Airlines was the most punctual of the 2 airlines on the route at 84.3%, while Frontier Airlines trailed at 77.5%.
September has been the best month (95% on time) and Sunday the weakest day of the week (72%).
0.6% of flights were cancelled, versus 1.8% nationally.
MIA to IAD 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 |
|---|---|---|---|---|
| United Airlines | 84.3% | 77 min | 0.4% | 512 |
| Frontier Airlines | 77.5% | 56 min | 1.8% | 113 |
80%+ good 70–79.9% fair <70% poor
Best time of day to fly MIA to IAD
On-time arrival % by scheduled departure hour (local time), 1,186 flights over 24 months.
Show the numbers
| Departure hour | On time | Cancelled | Flights |
|---|---|---|---|
| 7am–8am | Limited data | 5 | |
| 8am–9am | 91.0% | 0.8% | 123 |
| 9am–10am | 88.4% | 0.0% | 44 |
| 10am–11am | Limited data | 13 | |
| 11am–12pm | 86.8% | 0.0% | 38 |
| 12pm–1pm | 81.4% | 0.0% | 140 |
| 1pm–2pm | 84.2% | 0.3% | 619 |
| 2pm–3pm | Limited data | 3 | |
| 3pm–4pm | Limited data | 27 | |
| 4pm–5pm | Limited data | 9 | |
| 5pm–6pm | Limited data | 3 | |
| 6pm–7pm | 75.3% | 2.5% | 162 |
Best day of the week
24 months, by day of departure.
Best month to fly
24 months, by calendar month.
Holiday travel on MIA to IAD
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 | 24 | ||
| Christmas & New Year (Dec 20 - Jan 3) | 80.6% | -3.7 pts | 0.0% | 67 |
| Summer peak (Jun 15 - Aug 15) | 72.1% | -12.2 pts | 1.2% | 168 |
| All other days | 84.3% | — | 0.7% | 927 |
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).