Best Time to Fly STL to MCI: On-Time Stats by Hour & Airline
St Louis Lambert International → Kansas City International
Data through July 2026 · Last updated October 18, 2026
Over the last 12 months, 75.6% of St. Louis (STL) to Kansas City (MCI) flights arrived on time (1,020 scheduled flights). That is 2.0 points below the national average of 77.6%.
Southwest Airlines was the only reporting airline with regular flights on this route.
Over 24 months, Tuesday was the most reliable day (85% on time) and December the worst month (68%).
The cancellation rate was 0.3% (US average 1.8%).
STL to MCI on-time performance by airline
Last 12 months. Airlines with fewer than 30 completed flights are marked “limited data”.
| Airline | On time | Avg delay when late | Cancelled | Flights |
|---|---|---|---|---|
| Southwest Airlines | 75.6% | 52 min | 0.3% | 1,020 |
80%+ good 70–79.9% fair <70% poor
Best time of day to fly STL to MCI
On-time arrival % by scheduled departure hour (local time), 2,041 flights over 24 months.
Show the numbers
| Departure hour | On time | Cancelled | Flights |
|---|---|---|---|
| 8am–9am | 94.7% | 0.0% | 169 |
| 9am–10am | 88.8% | 0.5% | 189 |
| 10am–11am | 89.8% | 0.0% | 303 |
| 11am–12pm | 92.3% | 3.7% | 54 |
| 12pm–1pm | Limited data | 10 | |
| 1pm–2pm | 88.5% | 0.0% | 78 |
| 2pm–3pm | 83.6% | 0.6% | 178 |
| 3pm–4pm | 77.1% | 0.5% | 202 |
| 4pm–5pm | 64.0% | 0.0% | 147 |
| 5pm–6pm | Limited data | 26 | |
| 6pm–7pm | Limited data | 18 | |
| 7pm–8pm | Limited data | 28 | |
| 8pm–9pm | 74.3% | 0.5% | 211 |
| 9pm–10pm | 62.2% | 0.9% | 224 |
| 10pm–11pm | 61.8% | 2.0% | 204 |
Best day of the week
24 months, by day of departure.
Best month to fly
24 months, by calendar month.
Holiday travel on STL to MCI
On-time arrivals during holiday periods compared with all other days, last 24 months.
| Period | On time | vs other days | Cancelled | Flights |
|---|---|---|---|---|
| Thanksgiving week (Tue before to Mon after) | 74.3% | -6.4 pts | 0.0% | 35 |
| Christmas & New Year (Dec 20 - Jan 3) | 70.9% | -9.8 pts | 1.2% | 80 |
| Summer peak (Jun 15 - Aug 15) | 72.2% | -8.5 pts | 0.0% | 371 |
| All other days | 80.7% | — | 0.7% | 1,555 |
Monthly on-time trend
On-time arrival % each month, with the 12-month US average for reference.
What causes delays on this route
Share of reported delay minutes, last 12 months (BTS cause categories).