Airport month record

STLOCT

St. Louis Lambert International in October 2025

Departures: 5,611
Month: October 2025
National, same month: 79.7%
Carriers: 9

Historical statistics for October 2025, not live status or a forecast for this year’s October. For today’s conditions at STL, see live FAA status.

STL in October lands a B+, about a point worse than the national rate of 79.7%. About one flight in five arrives 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 5,611 flights, of which Delta Air Lines flew 499 at 89.9% on time.

Delta Air Lines is the most reliable of the three carriers covered here at 89.9% on time across 499 flights.

On time

78.5%

Arrivals under 15 minutes late, of 5,584 completed departures

Avg delay

60 min

Across delayed arrivals only, not all flights

Cancelled

0.27%

Nationally in October: 0.53%

Whole year

78.0%

STL across all twelve months

These figures cover 5,611 departures from St. Louis Lambert International in October 2025. On time means an arrival less than 15 minutes after the scheduled gate time, the DOT's threshold, and the national comparison uses every US departure in the same month rather than the whole year.

Against the year

October next to STL's other months

Against STL's own year, October ran level with the twelve-month rate of 78.0%, which makes it number seven of twelve months, best first. Cancellations were unusually low for STL in October, at 0.27% against 1.28% across the year. Either side of it, September ran 83.8% on time and November 80.1%, so a trip moved by a few weeks would have landed in a better stretch.

STL month by month
Month	Flights	On time	Avg delay	Cancelled	Grade
July 2025	5,855	71.7%	73 min	1.57%	C
August 2025	5,539	79.7%	71 min	0.96%	B+
September 2025	5,321	83.8%	58 min	0.34%	B+
October 2025 (this page)	5,611	78.5%	60 min	0.27%	B+
November 2025	5,202	80.1%	76 min	1.46%	B
December 2025	5,359	74.0%	75 min	0.90%	C+
January 2026	4,683	83.1%	74 min	3.46%	B−
February 2026	4,484	84.9%	64 min	1.32%	B
March 2026	5,400	75.3%	74 min	2.52%	B
April 2026	5,156	80.8%	65 min	0.80%	B+
May 2026	5,375	77.5%	74 min	0.84%	B+
June 2026	5,463	69.0%	68 min	1.17%	C

Departure window

The best time of day to leave STL in October

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 23 points, against 12 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am1,113 flights89.9%
8am–11am1,261 flights89.6%
11am–2pm707 flights79.3%
2pm–5pm921 flights69.4%
5pm–8pm894 flights66.6%
8pm–5am715 flights67.2%

Scale runs 60% to 95%. Rows with fewer than 30 flights show a dash.

Book the early departure. Flights leaving between 5am–8am arrive on time 89.9% of the time, against 66.6% for the evening window. That is 23 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 8am–11am window is the busiest, with 1,261 flights scheduled in it.

Across the week, Wednesday is the strongest day at 88.2% on time and Sunday the weakest at 68.0%. 20 points is a smaller lever than departure hour, but it is free.

Carrier by carrier

Which airlines ran best at STL in October

The choice of carrier is not cosmetic here. Delta Air Lines arrives on time 89.9% of the time; Southwest Airlines manages 77.8%. Sample sizes sit next to every figure, because a two-point gap across 3,567 flights means less than a ten-point one.

Carriers at STL in October 2025
Airline	Flights	On time	Avg delay	Cancelled	Grade
Southwest Airlines	3,567	77.8%	48 min	0.17%	B+
American Airlines	549	82.1%	113 min	0.55%	B+
Delta Air Lines	499	89.9%	88 min	0.20%	A+
United Airlinesthin sample	256	72.7%	51 min	0.00%	C+
Republic Airwaysthin sample	221	77.8%	71 min	1.36%	B
SkyWest Airlinesthin sample	189	64.6%	91 min	0.00%	D+
Envoy Airthin sample	125	66.1%	66 min	0.80%	C+
Frontier Airlinesthin sample	112	80.0%	116 min	0.89%	B+
Alaska Airlinesthin sample	61	88.3%	33 min	0.00%	A+

The spread between Delta and Southwest is 12 points, wide enough that it should decide the booking. On a hundred trips that is 12 more arrivals inside the on-time window.

Route by route

Busiest routes out of STL in October

Routes from STL in October 2025
Route	Flights	On time	Avg delay	Cancelled	Grade
STL to ATL · Atlantathin sample	348	90.2%	54 min	0.00%	A+
STL to DEN · Denverthin sample	334	80.2%	47 min	0.00%	B+
STL to ORD · Chicagothin sample	274	70.4%	69 min	0.00%	C+
STL to DCA · Washingtonthin sample	223	79.3%	52 min	0.00%	B+
STL to DFW · Dallas-Fort Worththin sample	209	79.0%	85 min	1.91%	B
STL to PHX · Phoenixthin sample	200	74.9%	77 min	0.00%	C+
STL to LGA · New Yorkthin sample	199	68.9%	54 min	2.01%	C
STL to MCO · Orlandothin sample	195	74.7%	71 min	0.00%	C+
STL to LAS · Las Vegasthin sample	188	76.6%	50 min	0.00%	B+
STL to DTW · Detroitthin sample	171	87.1%	84 min	0.58%	A+
STL to CLT · Charlottethin sample	162	84.5%	49 min	0.62%	B+
STL to DAL · Dallasthin sample	156	74.5%	73 min	1.28%	C
STL to BOS · Bostonthin sample	150	53.7%	61 min	0.67%	F+
STL to PHL · Philadelphiathin sample	147	82.2%	181 min	0.00%	B+
STL to MSP · Minneapolisthin sample	138	81.9%	71 min	0.00%	B+
STL to MDW · Chicagothin sample	130	80.8%	36 min	0.00%	B+
STL to HOU · Houstonthin sample	123	81.3%	59 min	0.00%	B+
STL to BNA · Nashvillethin sample	119	84.0%	54 min	0.00%	B+
STL to BWI · Baltimorethin sample	109	85.3%	49 min	0.00%	A+
STL to LAX · Los Angelesthin sample	96	61.5%	62 min	0.00%	D+
STL to TPA · Tampathin sample	95	76.8%	70 min	0.00%	B+
STL to EWR · Newarkthin sample	93	60.4%	87 min	2.15%	D
STL to SLC · Salt Lake Citythin sample	88	89.7%	36 min	0.00%	A+
STL to OMA · Omahathin sample	88	88.6%	32 min	0.00%	A+
STL to MCI · Kansas Citythin sample	88	77.3%	37 min	0.00%	B+

Delay causes

What held STL up in October

One category carries most of the weight here. Late-arriving aircraft accounts for 45% of the 72,000 delay minutes carriers reported, and the remaining four split what is left. The split is by minutes rather than by flights, so a few very long delays count for as much as many short ones.

Late-arriving aircraft
45%
Carrier
34%
National Airspace System
18%
Extreme weather
3%
Security
0%

45% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. That is a cascade, and cascades start small and grow through the day. Across 72,000 reported delay minutes here, that single category outweighs weather by 13 to one. It is the strongest argument for booking the first departure of the morning, when the aircraft has been sitting at the gate overnight with nothing to inherit. The split is drawn from 72,328 reported delay minutes.

Cancellations are rare at 0.27%, below the national 0.53% 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.

6.0% of arrivals land an hour or more late, close to the national 6.3%. 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 last about an hour, which a normal layover absorbs.

What to do with this

Flying from STL in October

For a October trip through STL: expect 78.5% on time and 0.27% cancelled, going by October 2025. The 5am–8am window was the strongest part of the day.

St. Louis Lambert International (STL), the whole year
STL in July71.7%
STL in August79.7%
STL in September83.8%
STL in November80.1%
STL in December74.0%
STL in January83.1%
STL in February84.9%
STL in March75.3%
STL in April80.8%
STL in May77.5%
STL in June69.0%

Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.

Key figures