IAD to SLC flight delays
Washington, VA (IAD) Salt Lake City, UT (SLC) · 1,827 miles
714 flights · January 2025 – August 2026 · US Bureau of Transportation Statistics
83.97%
Arrived on time
Within 15 minutes of schedule
1.12%
Cancelled
Share of scheduled flights
92 min
When late, late by
Average across delayed arrivals
16 min
Delay per flight
Averaged over every flight flown
What the record says about this route
The shape of the lateness matters here. Flights on this route are not late often, but when they are late they are late by about 92 minutes — long enough to lose a connection or an evening. The on-time percentage looks reassuring and understates the consequence of being on the wrong flight.
The season swings this route hard. In August it ran 21.5 points more punctual than in February — a difference bigger than the one between the best and worst airlines on most routes. If the date is flexible, it is worth more than the carrier.
Flights from Washington to Salt Lake City keep to schedule more reliably than most. On a route this punctual the day you fly matters more than the airline you pick.
The 2 airlines here are separated by under 1 point — close enough to call a tie. Choose on price and departure time.
Which airline should you fly on this route?
Over January 2025 – August 2026, Delta Air Lines arrived on time most often on IAD to SLC. United Airlines was late most often. Flights ran closest to schedule in August and worst in February.
Every airline on IAD to SLC
Ranked by how many flights each one operated. A carrier with fewer than 100 flights in the period is listed but not graded.
| Airline | Flights | On time | Cancelled | Avg delay | Grade |
|---|---|---|---|---|---|
| Delta Air Lines | 364 | 84.08% | 1.65% | 101 min | B |
| United Airlines | 350 | 83.86% | 0.57% | 83 min | B |
Month by month
Share of flights that arrived within 15 minutes of schedule, by month flown.
Other routes from Washington
Common questions
Are flights from Washington to Salt Lake City usually delayed?
83.97% of flights on the IAD to SLC route arrived within 15 minutes of schedule, so roughly 2 in every ten arrived late. That is better than the average route in this record.
Which airline is most on time from Washington to Salt Lake City?
Delta Air Lines, at 84.08% on time across 364 flights. The least punctual on the route was United Airlines at 83.86%.
How often are IAD to SLC flights cancelled?
1.12% of scheduled flights did not operate — about 11 in every thousand. That is in the normal range.
What is the best month to fly Washington to Salt Lake City?
August, when 93.7% of flights arrived on time. The worst was February at 72.2%.
When IAD to SLC flights are late, how late are they?
About 92 minutes on average across the flights that arrived more than 15 minutes behind schedule.
What these figures do and do not tell you
Everything on this page is counted from the flights that actually operated on IAD to SLC during January 2025 – August 2026, as reported by the airlines to the US Bureau of Transportation Statistics. "On time" is the federal definition: arriving at the gate within 15 minutes of the scheduled time.
A route's record is a description of the past, not a forecast. Weather, air traffic control and the aircraft's earlier flights that day drive most delays, and none of them are predictable from a historical rate. What the record does tell you is whether this route runs late more often than others, and which carrier on it has the better history — which is the part you can actually act on when you book.
Cancellations are counted separately from delays because they are a different problem for a traveller: a late flight still gets you there. How the grade is calculated →