ON TIMEBOARD

UA 2251 on time

United Airlines 2251: Chicago to San Francisco at 3:57 p.m. (past 12 months)

On time
66%
131 flights · likely 58–74%
Cancelled
0.0%
of scheduled flights
Typical arrival
+4 min
median vs schedule
When late
+77 min
average delay
Similar flights
64%
UA, same route & hour

About 1 in 3 UA 2251 flights from Chicago arrived 15+ minutes late, diverted or cancelled over the past year (34%); 0.0% were cancelled. The typical flight landed 4 minutes late.

UA 2251: ORD → SFO

Scheduled to leave Chicago at 3:57 p.m. local time. Over the past year it arrived on time 66% of the time (131 flights), in line with other UA flights on the route at that hour (64%). Last seen in the data Aug 31, 2026.

Month by month

40%70%100%Mar 2026: too few flights (3 flights)MarApr 2026: 64% on time (25 flights)64AprMay 2026: too few flights (11 flights)MayJun 2026: 63% on time (30 flights)63JunJul 2026: 77% on time (31 flights)77JulAug 2026: 61% on time (31 flights)61Aug

By day of week

DayFlightsOn time
Monday2060%
Tuesday19—
Wednesday19—
Thursday19—
Friday19—
Saturday15—
Sunday2075%

Why it was late

Late inbound plane 54%Air traffic & airport (NAS) 33%Airline (crew, maintenance, ops) 11%Severe weather 2%

All flights ORD → SFO · Connecting off UA 2251? Check the risk

Questions

How often is UA 2251 from ORD to SFO late?

United Airlines 2251 from Chicago, IL to San Francisco, CA arrived 15 or more minutes late, was diverted or was cancelled on 34% of 131 scheduled flights between September 2025 and August 2026. 0.0% were cancelled.

Flight numbers change. Figures cover flights with this airline, number and route only. "Likely range" is the 95% interval for the true on-time rate given the number of flights. This is history, not live status: check United Airlines for today's flight. Method.