IAD to MIA flight delays
Washington, VA (IAD) Miami, FL (MIA) · 922 miles
1,186 flights · July 2024 – July 2026 · US Bureau of Transportation Statistics
81.97%
Arrived on time
Within 15 minutes of schedule
0.76%
Cancelled
Share of scheduled flights
74 min
When late, late by
Average across delayed arrivals
14 min
Delay per flight
Averaged over every flight flown
What the record says about this route
Which airline you fly changes the odds here. United Airlines arrived on time 23.5 points more often than Frontier Airlines over the same period on the same route — same airports, same weather, same air traffic control. A gap that survives all of that is about how the two airlines are run.
The season swings this route hard. In October it ran 33.3 points more punctual than in July — 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.
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 74 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 Washington to Miami route sits close to the middle of the record — neither notably punctual nor notably late.
Which airline should you fly on this route?
Over July 2024 – July 2026, United Airlines arrived on time most often on IAD to MIA. Frontier Airlines was late most often. Flights ran closest to schedule in September and worst in July.
Every airline on IAD to MIA
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 |
|---|---|---|---|---|---|
| United Airlines | 1,020 | 85.21% | 0.49% | 66 min | B |
| Frontier Airlines | 166 | 61.73% | 2.41% | 95 min | F |
Month by month
Share of flights that arrived within 15 minutes of schedule, by month flown.
The return leg
MIA to IAD Miami back to Washington 81.77% on time BOther routes from Washington
Common questions
Are flights from Washington to Miami usually delayed?
81.97% of flights on the IAD to MIA 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 Miami?
United Airlines, at 85.21% on time across 1,020 flights. The least punctual on the route was Frontier Airlines at 61.73%.
How often are IAD to MIA flights cancelled?
0.76% of scheduled flights did not operate — about 8 in every thousand. That is in the normal range.
What is the best month to fly Washington to Miami?
October, when 97.3% of flights arrived on time. The worst was July at 64%.
When IAD to MIA flights are late, how late are they?
About 74 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 MIA during July 2024 – July 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 →