Best Time to Fly IAD to LAS: On-Time Stats by Hour & Airline
Washington Dulles International → Harry Reid International
Data through July 2026 · Last updated October 18, 2026
Over the last 12 months, 85.9% of Washington (IAD) to Las Vegas (LAS) flights arrived on time (1,077 scheduled flights). That is 8.3 points above the national average of 77.6%.
United Airlines was the most punctual of the 2 airlines on the route at 88.2%, while Frontier Airlines trailed at 63.6%.
October has been the best month (92% on time) and Friday the weakest day of the week (78%).
0.5% of flights were cancelled, versus 1.8% nationally.
IAD to LAS 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 | 88.2% | 74 min | 0.5% | 978 |
| Frontier Airlines | 63.6% | 58 min | 0.0% | 99 |
80%+ good 70–79.9% fair <70% poor
Best time of day to fly IAD to LAS
On-time arrival % by scheduled departure hour (local time), 2,266 flights over 24 months.
Show the numbers
| Departure hour | On time | Cancelled | Flights |
|---|---|---|---|
| 6am–7am | Limited data | 2 | |
| 7am–8am | 75.5% | 0.0% | 102 |
| 8am–9am | 90.2% | 1.1% | 362 |
| 9am–10am | 85.6% | 0.0% | 375 |
| 12pm–1pm | 86.3% | 0.2% | 492 |
| 1pm–2pm | 91.1% | 0.9% | 113 |
| 3pm–4pm | 65.1% | 0.0% | 87 |
| 5pm–6pm | 66.7% | 0.7% | 309 |
| 6pm–7pm | Limited data | 2 | |
| 7pm–8pm | 83.3% | 0.4% | 277 |
| 8pm–9pm | 75.6% | 0.0% | 90 |
| 10pm–11pm | 69.1% | 0.0% | 55 |
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 LAS
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) | 90.0% | +6.5 pts | 0.0% | 40 |
| Christmas & New Year (Dec 20 - Jan 3) | 89.2% | +5.7 pts | 0.0% | 74 |
| Summer peak (Jun 15 - Aug 15) | 72.9% | -10.6 pts | 0.0% | 417 |
| All other days | 83.5% | — | 0.5% | 1,735 |
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).