Carrier route record
DLMIA→SLC
Delta Air Lines · Miami to Salt Lake City
- 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 MIA to SLC lands a B+, 3 points better than the national rate of 77.3%. About one flight in five arrives 15 minutes late or worse, and those flights are late by about an hour on average. That rests on 364 flights, with a median arrival 3 minutes early.
The US average over the same twelve months is 77.3%, so there is little to separate Delta on MIA to SLC from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
80.1%
Arrivals under 15 minutes late, of 362 completed flights
Avg delay
65 min
Across delayed arrivals only, not all flights
Cancelled
0.55%
National rate is 1.89%
Whole route
77.3%
Every carrier on MIA to SLC, 818 flights
These figures cover 364 flights between September 2025 and August 2026. The median arrival is 3 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 MIA to SLC
Delta flew 364 of the 818 flights on MIA to SLC, about 44% of it. Its 80.1% on time is 3 points better than the route as a whole, which runs 77.3%. Ranked by on-time rate it is first of two carriers on the route, where the range runs from Delta at 80.1% to American at 75.1%.
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 | 80.1% | 65 min | 0.55% | B+ |
| American Airlines | 454 | 75.1% | 70 min | 0.66% | B+ |
Flight by flight
Delta flight numbers on MIA to SLC
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Departure window
When Delta runs best on this route
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 14 points, against half a point between the best and worst carrier.
- 5am–8am255 flights84.2%
- 8am–11am—
- 11am–2pm—
- 2pm–5pm4 flights—
- 5pm–8pm105 flights70.5%
- 8pm–5am—
Scale runs 60% to 90%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 84.2% of the time, against 70.5% for the evening window. That is 14 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 5am–8am window is the busiest, with 255 flights scheduled in it.
Across the year
Delta on MIA to SLC through the year
December is the weak month at 61.3% on time, against 96.7% in June. Winter delays cluster: a single storm system can account for most of a month's shortfall, so an average December hides both very good weeks and genuinely unflyable days. January was the busiest month here, with 31 flights.
Across the week, Tuesday is the strongest day at 88.2% on time and Sunday the weakest at 63.5%, a spread of 25 points.
Arrival by arrival
How late Delta on MIA to SLC runs when it is late
The 72 late arrivals split 31 under half an hour, 23 between 30 and 60 minutes, and 18 an hour or more.
- 15+ min early68 flights18.8%
- Within 15 min222 flights61.3%
- 15–29 min late31 flights8.6%
- 30–59 min late23 flights6.4%
- 1–2 hours late11 flights3.0%
- 2+ hours late7 flights1.9%
Scale runs 0% to 100%.
Share of 362 completed flights by arrival against schedule.
A late pushback is often recovered here: of 71 departures that left 15 minutes late or more, 22 still arrived on time. In the other direction, 23 flights left on time yet arrived 15 minutes late or more, so that delay built up after pushback: in the air, in a holding pattern or on the ground at SLC.
The worst days
Worst days for Delta on MIA to SLC
The latest arrival of the period was on 7 June 2026, 10 hours 58 minutes behind schedule; most of its delay minutes were filed as a late-arriving aircraft. On four of the five worst days the largest share was filed as carrier-caused (crew, maintenance, fuelling, baggage).
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 7 June 2026 | 10 hours 58 minutes | Late-arriving aircraft |
| 4 July 2026 | 9 hours 9 minutes | Carrier |
| 26 November 2025 | 4 hours 30 minutes | Carrier |
| 5 July 2026 | 3 hours 46 minutes | Carrier |
| 16 November 2025 | 3 hours 36 minutes | Carrier |
Delay causes
Why Delta runs late on this route
Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 4,664 reported delay minutes.
- 40%Carrier
- 38%Late-arriving aircraft
- 20%National Airspace System
- 2%Extreme weather
38% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 4,664 reported delay minutes here, that single category outweighs weather by 16 to one. The split is drawn from 4,664 reported delay minutes.
The largest share of delay minutes, 40%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 1,883 of the 4,664 delay minutes reported here.
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
5.0% of arrivals land an hour or more late, close to the national 8.3%, so a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last about an hour, which a normal layover absorbs.
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 88.1% on time across 364 flights, 8 points above 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 MIA to SLC
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 80.1% 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
- MIA to SLC, every carrier
- Delta on SLC to MIA, the return leg
- American Airlines on MIA to SLC75.1%
- Delta Air Lines network-wide record
- Miami International (MIA) delay statistics
- Salt Lake City International (SLC) delay statistics
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.05 million flight records
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.