Route profile
IAD→SLC
Flight reliability, delays and best times to fly from Washington to Salt Lake City, 1,828 miles.
Right now
Aviation weather is not currently a factor.
Aviation weather is not currently a factor.
Route reliability
July 2023 – July 2026
Better than 73% of comparable major US routes (4,598 compared)
Calculated from 1,702 flights. How this is calculated · What counts as on time
IAD → SLC arrives on time 84.4% of the time; the return trip, SLC → IAD, arrives on time 84.9% of the time.
IAD → SLC spends 25.8 minutes on the ground on a 1,828-mile trip: 18.2 minutes from pushback to wheels-up at IAD and 7.7 minutes from touchdown to gate at SLC.
Source: US DOT Bureau of Transportation Statistics · Data covering July 2023 – July 2026
What stands out
Every day of the week performs about the same on this route, steadier than 97% of 4,467 comparable routes.
86.3% on time on the best day (Wednesday) against 82.6% on the worst (Sunday).
Source: FlyerIntel analysis of US DOT BTS data · July 2023 – July 2026 · Ranked against every other route with the same kind of figure and at least 4,467 in the comparison.
What sets this route apart
Where IAD to SLC differs most from similar routes by hour, weekday, month and airline, July 2023 – July 2026.
IAD to SLC is at its best against routes of similar length for flights scheduled at 5 PM: 77.0% arrive on time, 4.6 points ahead of the 72.4% those routes manage at that hour. Against all other routes the gap is 7.2 points.
IAD to SLC holds up on Mondays better than routes of similar length do: 85.7% on time to their 77.1%, a 8.6 points lead. Against all other routes the gap is 8.5 points.
May is kinder to IAD to SLC than to routes of similar length: 91.5% on time against 75.7%, 15.8 points better. Against all other routes the gap is 16.3 points.
Delta Air Lines does better on IAD to SLC than on its routes of similar length: 87.5% on time here, 81.6% there, 5.9 points apart. Against all other routes the gap is 6 points.
IAD to SLC against comparable routes
July 2023 – July 2026| Measure | This route | Compared with | Them | Gap | Flights behind it |
|---|---|---|---|---|---|
| Hour: 5 PM departures | 77.0% | routes of similar length | 72.4% | +4.6 pts | 513 here, 81,070 there |
| Weekday: Monday | 85.7% | routes of similar length | 77.1% | +8.6 pts | 237 here, 180,724 there |
| Month: May | 91.5% | routes of similar length | 75.7% | +15.8 pts | 153 here, 105,559 there |
| Airline: Delta Air Lines | 87.5% | routes of similar length | 81.6% | +5.9 pts | 1,115 here, 302,131 there |
Each comparison pools the flights of other routes, with this route’s own left out. Similar length means within 15% of this route’s 1,828 miles, with at least 5 such routes. A bucket is set against the most comparable group that has enough flights: similar length, then the same origin (at least 3 routes), then all other routes. Hours, weekdays and months appear only where both sides have 120 completed flights, and airlines where both have 600. The gap must be at least 2 points and 2 standard errors, and only the largest gap each way is kept per measure. These are differences in the flights counted, not causes.
When it goes wrong
July 2023 – July 2026
26 min late
against a median of 8 min early
Percentiles over 1,702 operations; cancelled and diverted flights are counted separately.
Will your connection be tight enough?
Layovers at SLC after arriving from IAD.
| Connection time | Chance of missing | Reads as |
|---|---|---|
| 30 min | 31% | Likely to miss |
| 45 min | 15% | Some risk |
| 60 min | 9.5% | Some risk |
| 90 min | 5.9% | Some risk |
| 120 min | 3.9% | Low risk |
This is one leg of a connection. Gate changes and the next flight's own schedule matter too. And a connection can fail before delay is even the question — this route cancels 0.94% of the time and diverts 0.29% of the time, which a late arrival never shows up in.
Chance of missing is the share of 1,681 arrivals on this route that landed later than the connection time less 30 minutes to reach the next gate.
The worst tenth of arrivals on this route land at least 26 minutes late (90th-percentile gate arrival delay), over 1,702 operations.
Any other layover length: connection checker.
Why IAD → SLC runs late
July 2023 – July 2026
crew, maintenance, boarding and fueling, all within the carrier’s control
the inbound aircraft was late, so this flight started late
airspace and airport capacity, including weather-driven flow control
weather severe enough to stop this flight specifically
Share of the delay minutes US DOT attributed to each cause for IAD → SLC. Only delays of 15 minutes or more are attributed. What the five causes mean
Airlines on this route
Carriers with at least 200 flights, by the airline that operated each one.
| Carrier | Flights | On time | Cancelled | Median delay | Severe |
|---|---|---|---|---|---|
| Delta Air Lines | 1,127 | 87.5% | 0.89% | -9 min | 4.7% |
| United Airlines | 575 | 78.1% | 1.04% | -7 min | 8.3% |
Delta Air Lines flew 66.2% of the 1,702 flights listed.
Delta Air Lines arrived on time 9.4 percentage points more often than United Airlines on this route.
Flights on this route
Flight numbers with at least 600 operations here and still on the schedule.
| Flight | Scheduled | Operations | On time |
|---|---|---|---|
| DL432 Delta Air Lines | 7:05 AM | 814 | 87.2% |
Weekly and seasonal patterns
By day of week
Wednesday is historically the most reliable day and Sunday the least, a gap of 3.7 percentage points.
By month
- Jan: 79.3%
- Feb: 77.0%
- Mar: 88.3%
- Apr: 87.3%
- May: 91.5%
- Jun: 78.0%
- Jul: 79.3%
- Aug: 86.4%
- Sep: 91.7%
- Oct: 91.1%
- Nov: no data
- Dec: 82.2%
February is historically the weakest month and September the strongest, a spread of 14.7 percentage points.
Reliability over time
July 2023 – July 2026
Over the most recent 12 months (2025-08 to 2026-07), on-time arrivals averaged 82.7% against 83.1% in the 12 months before — broadly unchanged.
Data and methodology
Calculated by FlyerIntel from 1,702 IAD → SLC flight records from the US DOT Bureau of Transportation Statistics, covering July 2023 – July 2026. Late means 15 or more minutes past scheduled arrival; cancelled and diverted flights are left out of on-time rates.
Full methodology · Data sources · Report a problem
Related research: How Long a Layover Needs to Be · Two Airlines on One Route · Best Time of Day to Fly From Major US Airports
Analysis last recomputed