Schedule: a typical Thursday (the flights of Jul 30, 2026, re-dated). Real flights replace these once the FAA publishes them, usually about a day ahead.
UNITED · FLIGHT UA 503SCHEDULED · TYPICAL SCHEDULE
Tomorrow
UA 503 · BOS → ORD
departs 10:35 AM ET · arrives 12:28 PM CT
Forecast issued Wed 5:00 AM ET · 30h before departure
Odds over time
Arrive at ORD more than 15 minutes late?
22%chance · ±12 pts+6 pts · 24h
HOW SURE WE AREModerate. The odds now blend history with early weather forecasts.
How late will it get to ORD?
On time or early
78%
15–30 min late
4%
30 min–1 hour late
9%
1–2 hours late
6%
Over 2 hours late
3%
Cancelled
<1%
Gate arrival compared with the scheduled arrival. The ranges add up to 100%.