Route profile
STL→SLC
Flight reliability, delays and best times to fly from St. Louis to Salt Lake City, 1,156 miles.
Right now
Aviation weather is not currently a factor.
Aviation weather is not currently a factor.
Route reliability
July 2023 – July 2026
Better than 92% of comparable major US routes (4,598 compared)
Calculated from 3,016 flights. How this is calculated · What counts as on time
STL → SLC arrives on time 88.9% of the time; the return trip, SLC → STL, arrives on time 84.3% of the time, a 4.6-point gap between the two directions of the same city pair.
STL → SLC spends 20.2 minutes on the ground on a 1,156-mile trip: 12.5 minutes from pushback to wheels-up at STL and 7.7 minutes from touchdown to gate at SLC.
Source: US DOT Bureau of Transportation Statistics · Data covering July 2023 – July 2026
What stands out
Every day of the week performs about the same on this route, steadier than 97% of 4,467 comparable routes.
90.7% on time on the best day (Wednesday) against 87.0% on the worst (Saturday).
Source: FlyerIntel analysis of US DOT BTS data · July 2023 – July 2026 · Ranked against every other route with the same kind of figure and at least 4,467 in the comparison.
What sets this route apart
Where STL to SLC differs most from similar routes by hour, weekday, month and airline, July 2023 – July 2026.
STL to SLC is at its best against routes of similar length for flights scheduled at 5 PM: 91.1% arrive on time, 23.9 points ahead of the 67.2% those routes manage at that hour. Against all other routes the gap is 21.3 points.
STL to SLC holds up on Thursdays better than routes of similar length do: 90.6% on time to their 75.8%, a 14.8 points lead. Against all other routes the gap is 13.8 points.
July is kinder to STL to SLC than to routes of similar length: 86.6% on time against 68.3%, 18.3 points better. Against all other routes the gap is 16.9 points.
Delta Air Lines does better on STL to SLC than on its routes of similar length: 89.2% on time here, 80.5% there, 8.7 points apart. Against all other routes the gap is 7.7 points.
STL to SLC against comparable routes
July 2023 – July 2026| Measure | This route | Compared with | Them | Gap | Flights behind it |
|---|---|---|---|---|---|
| Hour: 5 PM departures | 91.1% | routes of similar length | 67.2% | +23.9 pts | 269 here, 139,791 there |
| Weekday: Thursday | 90.6% | routes of similar length | 75.8% | +14.8 pts | 445 here, 345,763 there |
| Month: July | 86.6% | routes of similar length | 68.3% | +18.3 pts | 367 here, 252,948 there |
| Airline: Delta Air Lines | 89.2% | routes of similar length | 80.5% | +8.7 pts | 2,945 here, 409,525 there |
Each comparison pools the flights of other routes, with this route’s own left out. Similar length means within 15% of this route’s 1,156 miles, with at least 5 such routes. A bucket is set against the most comparable group that has enough flights: similar length, then the same origin (at least 3 routes), then all other routes. Hours, weekdays and months appear only where both sides have 120 completed flights, and airlines where both have 600. The gap must be at least 2 points and 2 standard errors, and only the largest gap each way is kept per measure. These are differences in the flights counted, not causes.
When it goes wrong
July 2023 – July 2026
17 min late
against a median of 11 min early
Percentiles over 3,016 operations; cancelled and diverted flights are counted separately.
Will your connection be tight enough?
Layovers at SLC after arriving from STL.
| Connection time | Chance of missing | Reads as |
|---|---|---|
| 30 min | 22% | High risk |
| 45 min | 11% | Some risk |
| 60 min | 6.8% | Some risk |
| 90 min | 4.0% | Low risk |
| 120 min | 2.8% | Low risk |
This is one leg of a connection. Gate changes and the next flight's own schedule matter too. And a connection can fail before delay is even the question — this route cancels 0.66% of the time and diverts 0.17% of the time, which a late arrival never shows up in.
Chance of missing is the share of 2,991 arrivals on this route that landed later than the connection time less 30 minutes to reach the next gate.
The worst tenth of arrivals on this route land at least 17 minutes late (90th-percentile gate arrival delay), over 3,016 operations.
Any other layover length: connection checker.
Best time to fly
STL → SLC flights departing 5–9 AM arrived on time 93.1% of the time, against 83.8% for 6–9 PM departures, a gap of 9.3 percentage points.
By departure window
By departure hour
- 12 AM to 5 AM: too few flights to score
- 6 AM: 88.5% on time from 192 flights
- 7 AM: 93.8% on time from 787 flights
- 8 AM to 1 PM: too few flights to score
- 2 PM: 88.3% on time from 795 flights
- 3 PM to 4 PM: too few flights to score
- 5 PM: 91.1% on time from 272 flights
- 6 PM: 85.2% on time from 441 flights
- 7 PM: 81.7% on time from 267 flights
- 8 PM to 11 PM: too few flights to score
Departure windows with fewer than 120 flights are not scored.
Why STL → SLC runs late
July 2023 – July 2026
crew, maintenance, boarding and fueling, all within the carrier’s control
the inbound aircraft was late, so this flight started late
weather severe enough to stop this flight specifically
airspace and airport capacity, including weather-driven flow control
screening or terminal security incidents
Share of the delay minutes US DOT attributed to each cause for STL → SLC. Only delays of 15 minutes or more are attributed. What the five causes mean
Airlines on this route
Carriers with at least 200 flights, by the airline that operated each one.
| Carrier | Flights | On time | Cancelled | Median delay | Severe |
|---|---|---|---|---|---|
| Delta Air Lines | 2,970 | 89.2% | 0.67% | -11 min | 4.1% |
Flights on this route
Flight numbers with at least 600 operations here and still on the schedule.
| Flight | Scheduled | Operations | On time |
|---|---|---|---|
| DL2363 Delta Air Lines | 7:55 AM | 785 | 92.3% |
Weekly and seasonal patterns
By day of week
Wednesday is historically the most reliable day and Saturday the least, a gap of 3.7 percentage points.
By month
- Jan: 89.1%
- Feb: 84.2%
- Mar: 90.2%
- Apr: 85.7%
- May: 91.6%
- Jun: 87.1%
- Jul: 86.6%
- Aug: 89.0%
- Sep: 89.9%
- Oct: 91.8%
- Nov: 93.4%
- Dec: 88.2%
February is historically the weakest month and November the strongest, a spread of 9.2 percentage points.
Reliability over time
July 2023 – July 2026
Over the most recent 12 months (2025-08 to 2026-07), on-time arrivals averaged 87.4% against 91.4% in the 12 months before — declining by 4.0 percentage points.
Data and methodology
Calculated by FlyerIntel from 3,016 STL → SLC flight records from the US DOT Bureau of Transportation Statistics, covering July 2023 – July 2026. Late means 15 or more minutes past scheduled arrival; cancelled and diverted flights are left out of on-time rates.
Full methodology · Data sources · Report a problem
Related research: How Long a Layover Needs to Be · Two Airlines on One Route · Best Time of Day to Fly From Major US Airports
Analysis last recomputed