Carrier route record
DLSLC→MIA
Delta Air Lines · Salt Lake City to Miami
- Flights
- 364
- Period
- September 2025 to August 2026
- Share of route
- 44%
- Carriers
- 2
Historical statistics for September 2025 to August 2026, not live status. For today’s flights, check with Delta Air Lines.
Delta on SLC to MIA earns an A+. Close to nine flights in ten arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 11 points better than the national rate of 77.3%. When something does go wrong the average delay runs about an hour. That rests on 364 flights, with a median arrival 8 minutes early.
Set against the rest of the country, Delta's SLC to MIA record is 11 points better than the US average of 77.3%. That gap is worth roughly 108 fewer late arrivals for every thousand flights.
Key figures
On time
88.1%
Arrivals under 15 minutes late, of 362 completed flights
Avg delay
58 min
Across delayed arrivals only, not all flights
Cancelled
0.55%
National rate is 1.89%
Whole route
84.2%
Every carrier on SLC to MIA, 818 flights
These figures cover 364 flights between September 2025 and August 2026. The median arrival is 8 minutes early, which is the part an average hides: most flights here are fine, and the on-time rate is decided by a tail of badly late ones. On-time means under 15 minutes late, the DOT's own threshold.
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Carrier by carrier
Delta against every carrier on SLC to MIA
Delta flew 364 of the 818 flights on SLC to MIA, about 44% of it. Its 88.1% on time is 4 points better than the route as a whole, which runs 84.2%. Ranked by on-time rate it is first of two carriers on the route, where the range runs from Delta at 88.1% to American at 81.1%.
Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Delta Air Lines (this page)thin sample | 364 | 88.1% | 58 min | 0.55% | A+ |
| American Airlines | 454 | 81.1% | 83 min | 0.66% | B+ |
Flight by flight
Delta flight numbers on SLC to MIA
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Departure window
When Delta runs best on this route
Departure time is the single lever a traveller controls, and it moves the odds more than most people expect. Each bar below is the on-time rate for flights scheduled to leave inside that window, across 364 flights.
The overnight block holds up unusually well at 88.1% on time across 364 flights. Red-eyes fly into empty airspace and empty gates, and they are the first rotation of the aircraft's day rather than the last. The 8pm–5am window is the busiest, with 364 flights scheduled in it.
Across the year
Delta on SLC to MIA through the year
May is the best month on the calendar at 96.8% on time. Shoulder season thins the schedule and takes the summer weather with it, and the operation gets its margin back. January was the busiest month here, with 31 flights.
Across the week, Wednesday is the strongest day at 96.2% on time and Friday the weakest at 80.4%, a spread of 16 points.
Arrival by arrival
How late Delta on SLC to MIA runs when it is late
Most of the lateness is short. 23 of the 43 late arrivals were under half an hour behind, and 9 reached an hour or more.
- 15+ min early86 flights23.8%
- Within 15 min233 flights64.4%
- 15–29 min late23 flights6.4%
- 30–59 min late11 flights3.0%
- 1–2 hours late5 flights1.4%
- 2+ hours late4 flights1.1%
Scale runs 0% to 100%.
Share of 362 completed flights by arrival against schedule.
11 of 46 late departures made up the time and arrived on time, 24% of them. 8 flights left on time and still arrived late.
The worst days
Worst days for Delta on SLC to MIA
The latest arrival of the period was on 6 June 2026, 11 hours 21 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). The same cause led on three of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 6 June 2026 | 11 hours 21 minutes | Carrier |
| 30 October 2025 | 3 hours 11 minutes | Late-arriving aircraft |
| 26 December 2025 | 2 hours 39 minutes | Carrier |
| 2 August 2026 | 2 hours 31 minutes | Carrier |
| 17 August 2026 | 1 hour 29 minutes | Late-arriving aircraft |
Delay causes
Why Delta runs late on this route
Carrier accounts for 67% of the 2,498 delay minutes carriers reported here, and the remaining four split what is left.
- 67%Carrier
- 23%Late-arriving aircraft
- 10%National Airspace System
- 0%Extreme weather
The largest share of delay minutes, 67%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 1,668 of the 2,498 delay minutes reported here. The split is drawn from 2,498 reported delay minutes.
Cancellations are rare at 0.55%, below the national 1.89% and low enough to earn the plus on the grade. Roughly one flight in 100 is called off; the risk here is arriving late, not not arriving.
Connections and stage length
What a delay here costs
Badly late arrivals are rare here: only 2.5% land an hour or more behind schedule, against 8.3% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.
At 2,088 miles this is transcontinental flying, and long routes get a quiet structural advantage. Scheduled block time on a flight this length carries more padding in absolute minutes, so a twenty-minute late departure often still becomes an on-time arrival. Read the on-time rate here as slightly flattering next to a short-haul route with the same operational quality.
The return leg is a different operation and performs like one: it runs 80.1% on time across 364 flights, 8 points below this direction. Departure banks, aircraft rotations and the congestion at each end all differ, so scoring the two directions together would average away a real 8 points of difference.
One caution: this is a thin sample. 364 flights over twelve months is enough to clear this site's floor but not enough to pin the rate down tightly, and a single bad week moves it by more than a point. Treat the grade as a rough reading.
What to do with this
Booking Delta on SLC to MIA
Put together: treat all of this as provisional. 364 flights over twelve months is enough to clear this site's floor and not enough to be confident to better than a couple of points. The 88.1% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 362 completed flights over 12 months sit behind that.
Related
Where to go next
- SLC to MIA, every carrier
- Delta on MIA to SLC, the return leg
- American Airlines on SLC to MIA81.1%
- Delta Air Lines network-wide record
- Salt Lake City International (SLC) delay statistics
- Miami International (MIA) delay statistics
- Worst months to fly in the US, ranked by the data
- How to read this site: grades, sample sizes, and honest caveats
Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.