FlightRecord

St. Louis Lambert International Airport (STL): Delays & On-Time Performance

Data through May 2026

St. Louis Lambert International Airport (STL) is a tale of two seasons: departures ran 87% on-time in October 2024 but sank to 67% in July 2024. Across the year it averages 78% against a national 78%, over roughly 175 departures a day to 66 destinations.

Departures on-time
78%
left <15 min late
Avg dep delay
16 min
Arrivals on-time
80%
Cancelled
1.3%
Destinations
66
nonstop
Airlines
12

Monthly on-time trend

Monthly departure on-time percentage at STL50%75%100%June 2024: 74% on-time (5,825 flights)74Jun 2024July 2024: 67% on-time (6,029 flights)67August 2024: 80% on-time (5,749 flights)80September 2024: 87% on-time (5,496 flights)87Sep 2024October 2024: 87% on-time (5,762 flights)87November 2024: 86% on-time (5,263 flights)86December 2024: 78% on-time (5,384 flights)78Dec 2024January 2025: 83% on-time (4,717 flights)83February 2025: 83% on-time (4,419 flights)83March 2025: 81% on-time (5,379 flights)81Mar 2025April 2025: 81% on-time (5,439 flights)81May 2025: 77% on-time (5,628 flights)77June 2025: 72% on-time (5,733 flights)72Jun 2025July 2025: 70% on-time (5,855 flights)70August 2025: 78% on-time (5,539 flights)78September 2025: 83% on-time (5,321 flights)83Sep 2025October 2025: 77% on-time (5,611 flights)77November 2025: 78% on-time (5,202 flights)78December 2025: 70% on-time (5,359 flights)70Dec 2025January 2026: 81% on-time (4,683 flights)81February 2026: 81% on-time (4,484 flights)81March 2026: 71% on-time (5,400 flights)71Mar 2026April 2026: 79% on-time (5,156 flights)79May 2026: 74% on-time (5,375 flights)74

Best time of day to depart from STL

On-time percentage by scheduled departure hour at STL5 a.m.: 94% on-time (5,983 flights)56 a.m.: 92% on-time (9,555 flights)67 a.m.: 90% on-time (9,925 flights)78 a.m.: 88% on-time (9,224 flights)89 a.m.: 86% on-time (8,543 flights)910 a.m.: 86% on-time (9,291 flights)1011 a.m.: 83% on-time (6,043 flights)1112 p.m.: 82% on-time (4,638 flights)121 p.m.: 77% on-time (6,831 flights)132 p.m.: 74% on-time (7,597 flights)143 p.m.: 72% on-time (7,329 flights)154 p.m.: 66% on-time (6,052 flights)165 p.m.: 68% on-time (8,573 flights)176 p.m.: 68% on-time (8,678 flights)187 p.m.: 64% on-time (6,510 flights)198 p.m.: 65% on-time (7,105 flights)209 p.m.: 61% on-time (3,848 flights)2110 p.m.: 56% on-time (3,063 flights)22scheduled departure hour

Busiest routes from STL

RouteFlights/12moOn-timeAvg delay
STL → ATL3,71885%11 min
STL → DEN3,63677%17 min
STL → ORD3,06074%24 min
STL → LGA2,66079%15 min
STL → MCO2,49480%14 min
STL → DCA2,41075%19 min
STL → DFW2,35875%27 min
STL → PHX2,28778%17 min

Most reliable routes

  1. STL → SLC89%
  2. STL → PNS86%
  3. STL → ATL85%
  4. STL → DTW85%
  5. STL → MKE85%

Most delay-prone routes

  1. STL → BUR71%
  2. STL → SFO71%
  3. STL → ORD74%
  4. STL → BOS75%
  5. STL → SMF75%

Airline performance at STL

AirlineOn-time departuresAvg delayFlights
Delta Air Lines88%12 min10,832
Endeavor Air87%12 min831
Republic Airways85%13 min5,770
Alaska Airlines82%11 min1,572
American Airlines81%22 min12,247
PSA Airlines80%25 min1,498
Envoy Air78%17 min3,433
United Airlines78%20 min5,240
Southwest Airlines76%14 min81,407
Spirit Airlines74%22 min455
SkyWest Airlines74%27 min3,211
Frontier Airlines74%26 min2,312

Frequently asked questions

How often are flights delayed at STL?
22% of departures from St. Louis Lambert International Airport left 15+ minutes late between 2024-06 and 2026-05, with an average departure delay of 16 minutes. The national on-time average over the same period was 78%.
What is the best time of day to depart from STL?
Flights scheduled around 5 a.m. depart on time 94% of the time at STL, versus 56% around 10 p.m.. Booking before noon is the usual rule of thumb here.
What is the worst month for delays at STL?
In this dataset, July 2024 was the weakest month at STL, with 67% of departures on time.
How often are flights cancelled at STL?
1.3% of scheduled departures from STL were cancelled in this period, compared with a national rate of 1.6%.

Popular route pages from this airport

Based on 128,808 flights, 2024-06–2026-05. Source: US DOT Bureau of Transportation Statistics. Updated 2026-07-01.