Carrier performance at one airport
DL→SLC
Delta Air Lines at Salt Lake City International
- Departures
- 54,627
- Period
- June 2025 to May 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 77.4%. 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 54,627 flights, of which SkyWest Airlines flew 36,165 at 90.8% on time.
Measured against the airport rather than the country, Delta Air Lines runs about a point behind the 84.6% 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
83.5%
54,055 completed departures
Avg delay
62 min
Across delayed flights only
Cancelled
0.75%
At SLC, this carrier only
Rank here
#2
Of 8 carriers clearing the floor at SLC
These figures cover 55,000 flights between June 2025 and May 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 90.8% of the time; Alaska Airlines manages 73.6%. Sample sizes sit next to every figure, because a two-point gap across 1,578 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| SkyWest Airlines | 36,165 | 90.8% | 64 min | 0.43% | A+ |
| Delta Air Lines (this page) | 54,627 | 83.5% | 62 min | 0.75% | B+ |
| United Airlines | 4,851 | 80.0% | 72 min | 0.97% | B+ |
| Frontier Airlines | 3,432 | 79.1% | 88 min | 1.46% | B |
| Southwest Airlines | 11,356 | 78.3% | 51 min | 0.60% | B+ |
| American Airlines | 4,617 | 78.2% | 99 min | 2.43% | B |
| JetBlue Airways | 575 | 74.0% | 90 min | 3.48% | C− |
| Alaska Airlines | 1,578 | 73.6% | 48 min | 1.84% | C |
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 | 2,965 | 86.0% | 64 min | 0.57% | A+ |
| SLC to LAX · Los Angeles | 2,453 | 85.7% | 52 min | 0.45% | A+ |
| SLC to SEA · Seattle | 2,222 | 83.4% | 53 min | 0.59% | B+ |
| SLC to SAN · San Diego | 1,732 | 84.6% | 54 min | 0.64% | B+ |
| SLC to LAS · Las Vegas | 1,712 | 80.4% | 57 min | 0.58% | B+ |
| SLC to PHX · Phoenix | 1,709 | 87.3% | 56 min | 0.53% | A+ |
| SLC to SFO · San Francisco | 1,707 | 70.5% | 52 min | 0.82% | C+ |
| SLC to PDX · Portland | 1,697 | 87.8% | 56 min | 1.06% | A |
| SLC to DEN · Denver | 1,690 | 77.8% | 63 min | 0.24% | B+ |
| SLC to SNA · Santa Ana | 1,657 | 83.0% | 57 min | 0.54% | B+ |
| SLC to MSP · Minneapolis | 1,590 | 86.5% | 54 min | 0.25% | A+ |
| SLC to JFK · New York | 1,538 | 83.3% | 74 min | 1.63% | B |
| SLC to DTW · Detroit | 1,535 | 88.7% | 58 min | 0.20% | A+ |
| SLC to SMF · Sacramento | 1,510 | 87.8% | 63 min | 0.79% | A+ |
| SLC to DFW · Dallas-Fort Worth | 1,458 | 80.1% | 71 min | 1.23% | B |
| SLC to MCO · Orlando | 1,422 | 81.7% | 57 min | 0.63% | B+ |
| SLC to BOI · Boise | 1,234 | 84.1% | 62 min | 0.97% | B+ |
| SLC to AUS · Austin | 1,087 | 81.9% | 66 min | 0.55% | B+ |
| SLC to BOS · Boston | 1,083 | 83.4% | 60 min | 1.29% | B |
| SLC to MCI · Kansas City | 1,015 | 84.0% | 60 min | 1.08% | B |
| SLC to IAH · Houston | 1,011 | 82.3% | 83 min | 0.20% | B+ |
| SLC to ORD · Chicago | 1,010 | 76.6% | 73 min | 0.59% | B+ |
| SLC to SAT · San Antonio | 1,006 | 84.0% | 67 min | 0.89% | B+ |
| SLC to STL · St. Louis | 978 | 83.9% | 63 min | 0.61% | B+ |
| SLC to GEG · Spokane | 934 | 82.4% | 78 min | 0.64% | B+ |
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–8am3,020 flights90.0%
- 8am–11am11,440 flights87.4%
- 11am–2pm10,723 flights83.2%
- 2pm–5pm7,325 flights81.0%
- 5pm–8pm9,350 flights80.6%
- 8pm–5am12,769 flights82.4%
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 90.0% of the time, against 80.6% 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.
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.
Delay causes
What holds this operation up
- 54%Carrier
- 22%Late-arriving aircraft
- 20%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 299,000 of the 555,000 delay minutes reported here.
Cancellations are rare at 0.75%, below the national 1.80% 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.
5.1% of arrivals land an hour or more late, close to the national 8.2%. That is the figure that decides a connection, and it says a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route are the about an hour kind, which a normal layover absorbs.
54,627 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 17 points, which is the most any booking decision can do.
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 16.5% of the 54,627 flights in this analysis, against 22.6% 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 90.8% on time across 36,165 flights. Alaska Airlines is at the other end on 73.6%, a gap of 17 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 90.0% on time. The 5pm–8pm window is the weakest at 80.6%, 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
Source: US DOT Bureau of Transportation Statistics, on-time performance data, June 2025 to May 2026. Updated monthly. How this data is collected.