Airport month record
STLJUN
St. Louis Lambert International in June 2026
- Departures
- 5,463
- Month
- June 2026
- National, same month
- 74.3%
- Carriers
- 10
Historical statistics for June 2026, not live status or a forecast for this year’s June. For today’s conditions at STL, see live FAA status.
STL in June sits in the middle of the pack with a C. About seven flights in ten arrive on time by the DOT's definition, 5 points worse than the national rate of 74.3%. The late ones land a little over an hour behind schedule. That rests on 5,463 flights, of which Delta Air Lines flew 478 at 85.5% on time.
Delta Air Lines is the most reliable of the three carriers covered here at 85.5% on time across 478 flights.
Key figures
On time
69.0%
Arrivals under 15 minutes late, of 5,371 completed departures
Avg delay
68 min
Across delayed arrivals only, not all flights
Cancelled
1.17%
Nationally in June: 1.65%
Whole year
78.0%
STL across all twelve months
These figures cover 5,463 departures from St. Louis Lambert International in June 2026. 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
June next to STL's other months
Against STL's own year, June ran 9 points worse than the twelve-month rate of 78.0%, which makes it the worst of the twelve months in the data.
| 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 | 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 (this page) | 5,463 | 69.0% | 68 min | 1.17% | C |
Departure window
The best time of day to leave STL in June
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 36 points, against 21 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am863 flights89.0%
- 8am–11am1,226 flights82.2%
- 11am–2pm670 flights67.8%
- 2pm–5pm948 flights60.9%
- 5pm–8pm940 flights56.6%
- 8pm–5am816 flights52.6%
Scale runs 45% to 95%. Rows with fewer than 30 flights show a dash.
The 8pm–5am window is where this operation falls apart: 52.6% on time, against 89.0% for the 5am–8am slot. By evening the aircraft flying these rotations have absorbed a full day of small delays and there is no slack left to recover in. The 8am–11am window is the busiest, with 1,226 flights scheduled in it.
Across the week, Tuesday is the strongest day at 81.1% on time and Sunday the weakest at 59.6%. 21 points is a smaller lever than departure hour, but it is free.
Carrier by carrier
Which airlines ran best at STL in June
The choice of carrier is not cosmetic here. Delta Air Lines arrives on time 85.5% of the time; Southwest Airlines manages 64.2%. Sample sizes sit next to every figure, because a two-point gap across 3,319 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Southwest Airlines | 3,319 | 64.2% | 55 min | 0.24% | D+ |
| American Airlines | 526 | 75.8% | 109 min | 3.42% | B− |
| Delta Air Lines | 478 | 85.5% | 96 min | 1.67% | A |
| United Airlinesthin sample | 270 | 72.8% | 90 min | 1.48% | C |
| Republic Airwaysthin sample | 208 | 74.6% | 92 min | 3.85% | C− |
| SkyWest Airlinesthin sample | 155 | 73.9% | 117 min | 1.29% | C |
| Frontier Airlinesthin sample | 147 | 64.3% | 83 min | 4.08% | D− |
| Envoy Airthin sample | 120 | 76.9% | 99 min | 2.50% | B |
| PSA Airlinesthin sample | 120 | 68.5% | 140 min | 5.83% | C− |
| Alaska Airlinesthin sample | 120 | 83.3% | 45 min | 0.00% | B+ |
American Airlines cancels 3.4% 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
Busiest routes out of STL in June
| Route | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| STL to DEN · Denverthin sample | 358 | 66.4% | 63 min | 0.84% | C+ |
| STL to ATL · Atlantathin sample | 318 | 81.8% | 67 min | 1.26% | B |
| STL to ORD · Chicagothin sample | 304 | 70.3% | 116 min | 4.28% | C− |
| STL to DFW · Dallas-Fort Worththin sample | 240 | 65.3% | 117 min | 5.42% | C− |
| STL to MCO · Orlandothin sample | 204 | 75.0% | 64 min | 0.98% | B+ |
| STL to LGA · New Yorkthin sample | 204 | 74.4% | 52 min | 1.96% | C |
| STL to DCA · Washingtonthin sample | 198 | 64.6% | 71 min | 3.03% | D− |
| STL to LAS · Las Vegasthin sample | 180 | 54.8% | 76 min | 1.67% | F |
| STL to DTW · Detroitthin sample | 173 | 71.9% | 88 min | 2.31% | C |
| STL to DAL · Dallasthin sample | 170 | 56.0% | 65 min | 0.00% | D+ |
| STL to CLT · Charlottethin sample | 169 | 76.5% | 83 min | 0.59% | B+ |
| STL to PHX · Phoenixthin sample | 166 | 57.6% | 73 min | 0.60% | D+ |
| STL to MSP · Minneapolisthin sample | 165 | 69.9% | 74 min | 1.21% | C |
| STL to MDW · Chicagothin sample | 161 | 70.3% | 55 min | 1.24% | C |
| STL to PHL · Philadelphiathin sample | 147 | 77.4% | 74 min | 0.68% | B+ |
| STL to BOS · Bostonthin sample | 144 | 62.9% | 77 min | 0.69% | D+ |
| STL to HOU · Houstonthin sample | 126 | 65.1% | 49 min | 0.00% | C+ |
| STL to BWI · Baltimorethin sample | 118 | 71.3% | 57 min | 1.69% | C |
| STL to SEA · Seattlethin sample | 118 | 71.2% | 49 min | 0.00% | C+ |
| STL to BNA · Nashvillethin sample | 108 | 72.2% | 47 min | 0.00% | C+ |
| STL to MIA · Miamithin sample | 99 | 73.7% | 61 min | 0.00% | C+ |
| STL to TPA · Tampathin sample | 99 | 81.8% | 55 min | 0.00% | B+ |
| STL to EWR · Newarkthin sample | 90 | 81.4% | 72 min | 2.22% | B |
| STL to MCI · Kansas Citythin sample | 90 | 63.3% | 46 min | 0.00% | D+ |
| STL to SLC · Salt Lake Citythin sample | 90 | 83.3% | 119 min | 0.00% | B+ |
Delay causes
What held STL up in June
One category carries most of the weight here. Late-arriving aircraft accounts for 48% of the 113,000 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.
- 48%Late-arriving aircraft
- 26%Carrier
- 18%National Airspace System
- 6%Extreme weather
- 1%Security
48% 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 113,000 reported delay minutes here, that single category outweighs weather by 7 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 113,403 reported delay minutes.
Cancellations sit at 1.17% against a national 1.65%, which is ordinary. Diversions add another 0.51%.
For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 10.9% of arrivals land a full hour or more behind schedule, against 9.7% nationally. A 45-minute layover does not survive that, and no amount of walking quickly changes it. Ninety minutes is the honest minimum here, and two hours if the onward flight is on a separate ticket.
What to do with this
Flying from STL in June
For a June trip through STL: plan on this being one of the airport's harder months. The 5am–8am departures held up best at 89.0% on time, and with 10.9% of arrivals an hour or more late, a connection here deserves more slack than the same trip in February would.
Related
Where to go next
- St. Louis Lambert International (STL), the whole year
- STL in July71.7%
- STL in August79.7%
- STL in September83.8%
- STL in October78.5%
- 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%
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.