Route profile
IAD→SLC
Flight reliability, delays and best times to fly from Washington to Salt Lake City. · 1,828 miles
Right now
Current conditions at both ends of this route.
Weather conditions are slightly below ideal. FAA operational data — ground stops, ground delay programs and closures — is not currently available to FlyerIntel.
Weather conditions are associated with a higher chance of delays. FAA operational data — ground stops, ground delay programs and closures — is not currently available to FlyerIntel.
Airport conditions describe the airfield, not any individual flight. An airport operating normally is not a guarantee that a specific flight will depart on time.
Route reliability
July 2023 – June 2026
Better than 78% of comparable major US routes (4,577 compared)
Calculated from 1,640 flights. How this is calculated
Source: US DOT Bureau of Transportation Statistics · Data covering July 2023 – June 2026
Airlines on this route
Performance by the carrier that actually operated the flight.
| Carrier | Flights | On time | Cancelled | Median delay | Severe |
|---|---|---|---|---|---|
| Delta Air Lines | 1,096 | 87.4% | 0.91% | -9 min | 4.6% |
| United Airlines | 544 | 79.5% | 0.74% | -7 min | 7.1% |
Delta Air Lines arrived on time 7.8 percentage points more often than United Airlines on this route.
Source: FlyerIntel analysis of US DOT BTS data · July 2023 – June 2026 · Carriers with fewer than 200 flights on this route are not listed.
Other ways to fly Washington to Salt Lake City
Airport pairs serving the same journey, grouped by the DOT's own city-market definition. They do not perform the same way.
IAD → SLC is the most reliable pairing for this journey at 84.8% on time, against 79.6% for DCA → SLC.
Source: FlyerIntel analysis of US DOT BTS data · July 2023 – June 2026 · Grouped by DOT city market, which places Newark with the New York airports and Baltimore with the Washington ones.
Individual flights on this route
The same route is not equally reliable at every hour. These are the flight numbers with enough operating history to judge separately.
Source: FlyerIntel analysis of US DOT BTS data · July 2023 – June 2026 · Flight numbers with fewer than 270 operations on this route, or no longer scheduled, are not listed.
Weekly and seasonal patterns
By day of week
Monday is historically the most reliable day and Sunday the least, a gap of 4.0 percentage points.
By month
February is historically the weakest month and September the strongest, a spread of 14.7 percentage points.
Historical trend
On-time arrival rate by month.
Over the most recent 12 months (2025-07 to 2026-06), on-time arrivals averaged 83.9% against 82.4% in the 12 months before — broadly unchanged.
Source: FlyerIntel analysis of US DOT BTS data · July 2023 – June 2026
Data and methodology
All figures on this page are calculated by FlyerIntel from 1,640 IAD → SLC flight records published by the US DOT Bureau of Transportation Statistics, covering July 2023 – June 2026. A flight is counted as delayed when it arrives 15 or more minutes after its scheduled arrival time, following BTS methodology. Cancelled and diverted flights have no arrival time and are excluded from on-time rates rather than counted as late.