Flight OddsUA4427 IAD → STL
United Airlines · Washington, DC to St. Louis, MO · 306 flights observed, 2025-07-01 to 2026-05-20 · 696 mi
UA4427 covers more than one route in the data window — the stats below are for IAD → STL, the one it has flown most recently. The others are linked under “Other routes”.
On-time arrival
83%
Median delay
-15 min
90th percentile
+52 min
Cancellation rate
1%
How often is UA4427 on time?
Across 306 flights on IAD → STL from 2025-07-01 to 2026-05-20, UA4427 arrived within 15 minutes of schedule 83% of the time. The median arrival delay was -15 min, and the worst 10% of flights arrived +52 min or later. 1% of flights were cancelled.
Delay distribution
Arrival delay for completed flights (excludes cancellations and diversions).
| Arrival | Flights | Share |
|---|---|---|
| Early / on-time | 252 | 83% |
| 16-30 min | 15 | 5% |
| 31-60 min | 9 | 3% |
| 61-120 min | 10 | 3% |
| 2+ hrs | 17 | 6% |
Performance by month
| Month | Flights | On-time | Avg delay |
|---|---|---|---|
| 2025-07 | 30 | 87% | +11 min |
| 2025-08 | 31 | 77% | +14 min |
| 2025-09 | 28 | 93% | -16 min |
| 2025-10 | 20 | 85% | -4 min |
| 2025-11 | 30 | 87% | -4 min |
| 2025-12 | 31 | 65% | +30 min |
| 2026-01 | 29 | 72% | +22 min |
| 2026-02 | 27 | 85% | +0 min |
| 2026-03 | 31 | 84% | +6 min |
| 2026-04 | 27 | 93% | -17 min |
| 2026-05 | 19 | 95% | -4 min |
Performance by day of week
| Day | Flights | On-time |
|---|---|---|
| Mon | 44 | 77% |
| Tue | 43 | 86% |
| Wed | 41 | 83% |
| Thu | 46 | 85% |
| Fri | 46 | 85% |
| Sat | 38 | 87% |
| Sun | 45 | 80% |
Other routes
Related
Based on US Department of Transportation Bureau of Transportation Statistics on-time data. Loading live conditions and full charts…