80% of flights from Washington to Salt Lake City arrived on time over the past 12 months. That is about the typical U.S. route. The 7 a.m. departures ran on time 84% of the time; the 5 p.m. ones 77%. Most reliable airline: Delta Air Lines (84%). 9% of flights arrived more than an hour late or not at all.
How late?
The on-time rate treats a flight 20 minutes late the same as one 5 hours late. Here's the split for IAD → SLC: when a flight was late, it was under 45 minutes late 49% of the time. About 1 in 13 flights landed an hour or more late, and 1 in 29 three hours or more; 1.4% were cancelled outright.
- On time or early80%
- 15–30 min late6.3%
- 30–60 min late4.3%
- 1–2 hours late3.0%
- 2–3 hours late1.3%
- 3+ hours late3.4%
- Diverted0.1%
- Cancelled1.4%
Share of all 701 scheduled flights, past 12 months, by arrival time against schedule.
By airline
| Airline | Flights | On time | Cancelled | Typical arrival | 1h+ late | Avg when late | Operated by |
|---|---|---|---|---|---|---|---|
| Delta Air Lines | 364 | 84% | 1.7% | −6 min | 5.5% | +100 min | Delta Air Lines |
| United Airlines | 337 | 76% | 1.2% | −5 min | 10.1% | +106 min | United Airlines |
Airline = the name on the ticket. Regional flights (e.g. "Delta Connection") count under the ticketing airline, and the operator is listed.
Best time of day to fly
On-time rate by scheduled departure hour (local time at IAD). Delays build through the day as late planes knock on, so early flights usually do best.
By airline and hour
| Departs | Delta Air Lines | United Airlines |
|---|---|---|
| 7 a.m. | 84% | — |
| 5 p.m. | — | 77% |
By month
Each calendar month pooled over 2023–2026. Best: September (92%). Worst: February (76%).
By day of week
| Day | Flights | On time | Cancelled |
|---|---|---|---|
| Monday | 101 | 80% | 3.0% |
| Tuesday | 98 | — | — |
| Wednesday | 98 | — | — |
| Thursday | 101 | 74% | 1.0% |
| Friday | 99 | — | — |
| Saturday | 102 | 85% | 1.0% |
| Sunday | 102 | 73% | 2.9% |
Why flights were late
Share of delay minutes on flights 15+ minutes late, as reported to BTS by the airlines.
Cancellations: weather 7 · airline 3
Month by month
Not enough months with data to draw a trend.
Flight numbers on this route
Regular flights with at least 120 scheduled trips in the past year. Sorted by departure time.
| Flight | Departs | Flights | On time | Cancelled | Typical arrival | Operated by |
|---|---|---|---|---|---|---|
| DL 432 | 7:05 a.m. | 364 | 84% | 1.7% | −6 min | Delta Air Lines |
| UA 2410 | 5:50 p.m. | 337 | 76% | 1.2% | −5 min | United Airlines |
Nearby airport alternatives
Other ways to make the same trip, using airports within 60 miles of Washington or Salt Lake City. None has been clearly more reliable than IAD → SLC.
| Route | Flights | On time | Cancelled |
|---|---|---|---|
| IAD → SLC (this route) | 701 | 80% | 1.4% |
| BWI → SLC Baltimore/Washington to Salt Lake City | 769 | 75% | 1.8% |
Questions
How often are flights from IAD to SLC on time?
80% of 701 scheduled flights from Washington, DC to Salt Lake City, UT arrived within 15 minutes of schedule between September 2025 and August 2026. 1.4% were cancelled.
What is the best time of day to fly IAD to SLC?
Flights scheduled to leave at 7 a.m. were the most reliable (84% on time). The 5 p.m. departures were the least (77%).
Which airline is most on time from IAD to SLC?
Delta Air Lines: 84% of its 364 flights on the route arrived on time. United Airlines: 76%.
What month has the most delays from IAD to SLC?
February (76% on time). The best month is September (92%), over 2023–2026.
Related
- SLC → IAD (return)
- Washington Dulles (IAD) delays by hour
- Flights into Salt Lake City (SLC)
- Delta Air Lines on-time record
- United Airlines on-time record
- Connecting off this flight? Check the risk
Domestic flights by the airlines that report to the U.S. DOT, plus their regional partners. "On time" means arriving less than 15 minutes after schedule; cancelled and diverted flights count as not on time. Past performance is a guide, not a forecast. Method.