Carrier performance at one airport
DL→SLC
Delta Air Lines at Salt Lake City International
- Departures
- 54,634
- Period
- July 2025 to June 2026
- Routes
- 25
- Rank here
- #2 of 8
Delta Air Lines at Salt Lake City lands a B+, 6 points better than the national rate of 77.6%. About one flight in six arrive 15 minutes late or worse, and those flights are late by about an hour on average. That is a workable record, not a spotless one. That rests on 54,634 flights, of which SkyWest Airlines flew 36,254 at 90.7% on time.
Measured against the airport rather than the country, Delta Air Lines runs about a point behind the 84.8% weighted average across all carriers at SLC. That is the comparison worth making: every operator here works the same runways, the same airspace and the same weather.
Key figures
On time
83.8%
54,072 completed departures
Avg delay
62 min
Across delayed flights only
Cancelled
0.74%
At SLC, this carrier only
Rank here
#2
Of 8 carriers clearing the floor at SLC
These figures cover 55,000 flights between July 2025 and June 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.
Against the competition
Every carrier at SLC, ranked
The choice of carrier is not cosmetic here. SkyWest Airlines arrives on time 90.7% of the time; JetBlue Airways manages 75.3%. Sample sizes sit next to every figure, because a two-point gap across 576 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| SkyWest Airlines | 36,254 | 90.7% | 65 min | 0.43% | A+ |
| Delta Air Lines (this page) | 54,634 | 83.8% | 62 min | 0.74% | B+ |
| United Airlines | 4,875 | 80.2% | 73 min | 1.01% | B |
| Frontier Airlines | 3,504 | 79.8% | 88 min | 1.46% | B |
| American Airlines | 4,635 | 78.7% | 102 min | 2.55% | B |
| Southwest Airlines | 11,290 | 78.1% | 50 min | 0.56% | B+ |
| Alaska Airlines | 1,621 | 75.5% | 49 min | 1.73% | B |
| JetBlue Airways | 576 | 75.3% | 90 min | 3.47% | B− |
JetBlue Airways cancels 3.5% of what it schedules here, the highest in the table. A cancelled flight never appears in an on-time rate, so read that column alongside the punctuality one rather than after it.
Route by route
Where Delta Air Lines flies from SLC
Delta Air Lines operates 25 routes out of SLC with enough volume to report. Route records inside one carrier at one airport still spread widely, because a short shuttle and a transcontinental have very different exposure to a late inbound.
| Route | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| SLC to ATL · Atlanta | 2,966 | 87.4% | 63 min | 0.54% | A+ |
| SLC to LAX · Los Angeles | 2,454 | 85.4% | 51 min | 0.41% | A+ |
| SLC to SEA · Seattle | 2,222 | 83.3% | 54 min | 0.54% | B+ |
| SLC to SAN · San Diego | 1,731 | 83.8% | 55 min | 0.81% | B+ |
| SLC to LAS · Las Vegas | 1,714 | 80.2% | 57 min | 0.58% | B+ |
| SLC to PHX · Phoenix | 1,708 | 87.9% | 56 min | 0.53% | A+ |
| SLC to SFO · San Francisco | 1,706 | 67.4% | 52 min | 0.88% | C+ |
| SLC to PDX · Portland | 1,697 | 87.5% | 55 min | 1.12% | A |
| SLC to DEN · Denver | 1,690 | 79.4% | 64 min | 0.24% | B+ |
| SLC to SNA · Santa Ana | 1,655 | 84.0% | 58 min | 0.48% | B+ |
| SLC to MSP · Minneapolis | 1,589 | 86.5% | 54 min | 0.25% | A+ |
| SLC to DTW · Detroit | 1,539 | 89.4% | 61 min | 0.19% | A+ |
| SLC to JFK · New York | 1,538 | 83.5% | 68 min | 1.63% | B |
| SLC to SMF · Sacramento | 1,509 | 87.3% | 63 min | 0.86% | A+ |
| SLC to DFW · Dallas-Fort Worth | 1,458 | 80.4% | 70 min | 1.30% | B |
| SLC to MCO · Orlando | 1,415 | 82.9% | 56 min | 0.64% | B+ |
| SLC to BOI · Boise | 1,223 | 84.7% | 59 min | 1.06% | B |
| SLC to BOS · Boston | 1,083 | 83.3% | 60 min | 1.29% | B |
| SLC to AUS · Austin | 1,081 | 82.6% | 66 min | 0.56% | B+ |
| SLC to MCI · Kansas City | 1,012 | 85.3% | 60 min | 1.09% | A |
| SLC to IAH · Houston | 1,011 | 82.1% | 81 min | 0.20% | B+ |
| SLC to ORD · Chicago | 1,010 | 76.8% | 70 min | 0.69% | B+ |
| SLC to SAT · San Antonio | 1,007 | 84.1% | 65 min | 0.79% | B+ |
| SLC to STL · St. Louis | 978 | 83.8% | 63 min | 0.51% | B+ |
| SLC to BNA · Nashville | 933 | 85.4% | 52 min | 0.54% | A+ |
Departure window
Best time of day for this operation
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 55,000 flights.
- 5am–8am3,058 flights90.1%
- 8am–11am11,400 flights87.6%
- 11am–2pm10,781 flights83.7%
- 2pm–5pm7,341 flights81.0%
- 5pm–8pm9,368 flights80.9%
- 8pm–5am12,686 flights82.7%
Scale runs 70% to 95%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 90.1% of the time, against 80.9% for the evening window. That is 9 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 8pm–5am window is the busiest, with 12,686 flights scheduled in it.
Across the year
Seasonal pattern
July is the worst month at 77.5% on time, 10 points below September, the best at 87.2%. Summer afternoon convection and peak-season schedules land on the same weeks every year, so this is a pattern you can book around rather than a run of bad luck. July was the busiest month here, with 4,779 flights.
Delay causes
What holds this operation up
- 54%Carrier
- 22%Late-arriving aircraft
- 21%National Airspace System
- 4%Extreme weather
- 0%Security
The largest share of delay minutes, 54%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 290,000 of the 540,000 delay minutes reported here. The split is drawn from 539,597 reported delay minutes.
Cancellations are rare at 0.74%, below the national 1.81% 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.
Badly late arrivals are rare here: only 4.9% land an hour or more behind schedule, against 8.1% 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.
54,634 flights sit behind these numbers, which is a large enough sample that the headline rate is not moving on noise. Where a sub-group falls below 30 flights the site shows a dash instead of a percentage.
Put together: take the 5am–8am departure, avoid July if the dates are flexible, and if two carriers are within a few dollars of each other, SkyWest is the one with the record behind it. None of that guarantees an on-time arrival; it moves the odds by 15 points, which is the most any booking decision can do. 54,072 completed flights over 12 months sit behind that.
Common questions
Delta Air Lines at SLC
How often is Delta Air Lines at SLC delayed?
About one flight in six arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 16.2% of the 54,634 flights in this analysis, against 22.4% nationally. Delayed flights are late by about an hour on average.
Which airline is most reliable on Delta Air Lines at SLC?
SkyWest Airlines leads at 90.7% on time across 36,254 flights. JetBlue Airways is at the other end on 75.3%, a gap of 15 points. Sample size matters as much as the percentage: a rate built from a few hundred flights moves around far more than one built from ten thousand.
What time of day has the fewest delays on Delta Air Lines at SLC?
The 5am–8am departure window is the strongest at 90.1% on time. The 5pm–8pm window is the weakest at 80.9%, 9 points behind. Later departures inherit delays from earlier flights the same aircraft has already flown, which is why the curve slopes the way it does.
How bad are July delays on Delta Air Lines at SLC?
July is the weakest month at 77.5% on time, compared with 87.2% in September. Across the year that is 10 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.
Related
Where to go next
- Delta Air Lines network-wide record
- Salt Lake City International (SLC) all carriers
- SLC to ATL route record87.4%
- SLC to LAX route record85.4%
- SLC to SEA route record83.3%
- SLC to SAN route record83.8%
- The best time of day to fly, according to 7.04 million flight records
- Do budget airlines really get delayed more? The numbers
Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Updated monthly. How this data is collected.