Flight OddsUA521 BOS → EWR
United Airlines · Boston, MA to Newark, NJ · 132 flights observed, 2025-08-19 to 2026-02-11 · 200 mi
UA521 covers more than one route in the data window — the stats below are for BOS → EWR, the one it has flown most recently. The others are linked under “Other routes”.
On-time arrival
54%
Median delay
+13 min
90th percentile
+123 min
Cancellation rate
6%
How often is UA521 on time?
Across 132 flights on BOS → EWR from 2025-08-19 to 2026-02-11, UA521 arrived within 15 minutes of schedule 54% of the time. The median arrival delay was +13 min, and the worst 10% of flights arrived +123 min or later. 6% of flights were cancelled.
Delay distribution
Arrival delay for completed flights (excludes cancellations and diversions).
| Arrival | Flights | Share |
|---|---|---|
| Early / on-time | 67 | 54% |
| 16-30 min | 11 | 9% |
| 31-60 min | 14 | 11% |
| 61-120 min | 18 | 15% |
| 2+ hrs | 14 | 11% |
Performance by month
| Month | Flights | On-time | Avg delay |
|---|---|---|---|
| 2025-08 | 11 | 45% | +40 min |
| 2025-09 | 24 | 46% | +52 min |
| 2025-10 | 25 | 32% | +70 min |
| 2025-11 | 21 | 67% | +31 min |
| 2025-12 | 13 | 38% | +20 min |
| 2026-01 | 20 | 75% | +6 min |
| 2026-02 | 10 | 90% | -4 min |
Performance by day of week
| Day | Flights | On-time |
|---|---|---|
| Mon | 21 | 62% |
| Tue | 24 | 46% |
| Wed | 23 | 65% |
| Thu | 19 | 47% |
| Fri | 21 | 48% |
| Sat | No data | — |
| Sun | 16 | 56% |
Other routes
Related
Based on US Department of Transportation Bureau of Transportation Statistics on-time data. Loading live conditions and full charts…