Washington (IAD) to Las Vegas (LAS): On-Time Performance
Data through May 2026
When you fly IAD to LAS matters as much as anything else about the booking: the route swung from 98% on-time in October 2024 to just 66% in June 2025. Across the full period the route averages 83% on-time against a national 78%. Morning departures also hold up better than evening ones (89% vs 74%), which matters most in the rough months.
- On-time
- 83%
- arrived <15 min late
- Avg delay
- 13 min
- completed flights
- Cancelled
- 0.5%
- Flights/day
- 3.1
- last 12 months
- Duration
- 5h 14m
- scheduled
- Distance
- 2,065 mi
Best airline from IAD to LAS
2 airlines flew this route regularly between 2024-06 and 2026-05.
| Airline | On-time | Avg delay | Cancelled | Flights |
|---|---|---|---|---|
| United Airlinesmost reliable | 83% | 12 min | 0.6% | 2,082 |
| Frontier Airlines | 73% | 21 min | 0.0% | 124 |
Monthly on-time trend
Best time to fly from IAD to LAS
Aim for departures around 1 p.m. (94% on-time); avoid 3 p.m. departures (64%).
By day of week
| Day | On-time | Avg delay |
|---|---|---|
| Monday | 80% | 15 min |
| Tuesday | 86% | 10 min |
| Wednesdaybest | 87% | 11 min |
| Thursday | 81% | 13 min |
| Friday | 79% | 14 min |
| Saturday | 84% | 11 min |
| Sunday | 81% | 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 aircraft40%
- Airline operations25%
- National airspace system25%
- Weather11%
Frequently asked questions
- How often are flights from IAD to LAS delayed?
- 18% of IAD–LAS flights arrived 15 or more minutes late (the US DOT definition of a delay) between 2024-06 and 2026-05. The average arrival delay across completed flights was 13 minutes.
- Which airline is most reliable from IAD to LAS?
- United Airlines has the best on-time record on this route at 83%, based on 2,082 flights. 2 airlines flew IAD–LAS frequently enough to compare in this period.
- What is the best time of day to fly from IAD to LAS?
- Departures around 1 p.m. have the best record (94% on-time), while departures around 3 p.m. have the worst (64%). As on most US routes, delays accumulate through the day, so earlier flights are generally safer.
- How long is the flight from IAD to LAS?
- The scheduled IAD–LAS flight time averages 5h 14m over 2,065 miles. Actual arrival times vary — flights on this route land 15+ minutes late 18% of the time.
- How often are IAD to LAS flights cancelled?
- 0.5% of scheduled flights on this route were cancelled between 2024-06 and 2026-05, at or below the national rate of 1.6%.
- What is the worst month to fly from IAD to LAS?
- June 2025 was the roughest month in this dataset, with only 66% of arrivals on time. The best was October 2024 at 98%. If your dates are flexible, that 32-point gap is worth planning around.
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Based on 2,206 flights, 2024-06–2026-05. Source: US DOT Bureau of Transportation Statistics. Updated 2026-07-01.