83% of flights from Salt Lake City to Washington arrived on time over the past 12 months. That is better than the typical U.S. route. The 10 a.m. departures ran on time 87% of the time; the 5 p.m. ones 78%. Most reliable airline: United Airlines (86%). 7% 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 SLC → IAD: when a flight was late, it was under 45 minutes late 58% of the time. About 1 in 21 flights landed an hour or more late, and 1 in 140 three hours or more; 1.7% were cancelled outright.
- On time or early83%
- 15–30 min late6.3%
- 30–60 min late4.3%
- 1–2 hours late3.3%
- 2–3 hours late0.7%
- 3+ hours late0.7%
- Diverted0.3%
- Cancelled1.7%
Share of all 702 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 | 79% | 1.7% | −7 min | 6.0% | +57 min | Delta Air Lines |
| United Airlines | 338 | 86% | 1.8% | −9 min | 3.3% | +68 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 SLC). 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 |
|---|---|---|
| 9 a.m. | — | 85% |
| 10 a.m. | — | 87% |
| 5 p.m. | 78% | — |
By month
Each calendar month pooled over 2023–2026. Best: November (94%). Worst: July (67%).
By day of week
| Day | Flights | On time | Cancelled |
|---|---|---|---|
| Monday | 105 | 85% | 3.8% |
| Tuesday | 99 | — | — |
| Wednesday | 97 | — | — |
| Thursday | 98 | — | — |
| Friday | 102 | 81% | 0.0% |
| Saturday | 99 | — | — |
| Sunday | 102 | 72% | 4.9% |
Why flights were late
Share of delay minutes on flights 15+ minutes late, as reported to BTS by the airlines.
Cancellations: weather 8 · airline 4
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 847 | 5:35 p.m. | 364 | 79% | 1.7% | −7 min | Delta Air Lines |
Worst days in the past year
| Date | Flights | On time | Cancelled |
|---|---|---|---|
| Aug 10, 2026 | 3 | 67% | 0 |
Nearby airport alternatives
Other ways to make the same trip, using airports within 60 miles of Salt Lake City or Washington. None has been clearly more reliable than SLC → IAD.
| Route | Flights | On time | Cancelled |
|---|---|---|---|
| SLC → IAD (this route) | 702 | 83% | 1.7% |
| SLC → BWI Salt Lake City to Baltimore/Washington | 769 | 80% | 1.6% |
Questions
How often are flights from SLC to IAD on time?
83% of 702 scheduled flights from Salt Lake City, UT to Washington, DC arrived within 15 minutes of schedule between September 2025 and August 2026. 1.7% were cancelled.
What is the best time of day to fly SLC to IAD?
Flights scheduled to leave at 10 a.m. were the most reliable (87% on time). The 5 p.m. departures were the least (78%).
Which airline is most on time from SLC to IAD?
United Airlines: 86% of its 338 flights on the route arrived on time. Delta Air Lines: 79%.
What month has the most delays from SLC to IAD?
July (67% on time). The best month is November (94%), over 2023–2026.
Related
- IAD → SLC (return)
- Salt Lake City (SLC) delays by hour
- Flights into Washington Dulles (IAD)
- 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.