About 1 in 5 UA 2331 flights from Washington arrived 15+ minutes late, diverted or cancelled over the past year (21%); 0.8% were cancelled. The typical flight landed 6 minutes early.
UA 2331: IAD → ORD
Scheduled to leave Washington at 1:15 p.m. local time. Over the past year it arrived on time 79% of the time (365 flights), in line with other UA flights on the route at that hour (79%). Last seen in the data Aug 31, 2026.
Month by month
By day of week
| Day | Flights | On time |
|---|---|---|
| Monday | 53 | 77% |
| Tuesday | 52 | 85% |
| Wednesday | 52 | 83% |
| Thursday | 52 | 77% |
| Friday | 52 | 77% |
| Saturday | 52 | 83% |
| Sunday | 52 | 71% |
Why it was late
All flights IAD → ORD · Connecting off UA 2331? Check the risk
UA 2331: TPA → IAD
Scheduled to leave Tampa at 9:00 a.m. local time. Over the past year it arrived on time 92% of the time (318 flights), in line with other UA flights on the route at that hour (93%). Last seen in the data Aug 31, 2026.
Month by month
By day of week
| Day | Flights | On time |
|---|---|---|
| Monday | 47 | 96% |
| Tuesday | 42 | 93% |
| Wednesday | 42 | 98% |
| Thursday | 47 | 94% |
| Friday | 47 | 89% |
| Saturday | 47 | 89% |
| Sunday | 46 | 89% |
Why it was late
All flights TPA → IAD · Connecting off UA 2331? Check the risk
UA 2331: ORD → BOS
Scheduled to leave Chicago at 6:20 p.m. local time. Over the past year it arrived on time 52% of the time (123 flights), worse than other UA flights on the route at that hour (55%). Last seen in the data Aug 31, 2026.
Month by month
By day of week
| Day | Flights | On time |
|---|---|---|
| Monday | 18 | — |
| Tuesday | 17 | — |
| Wednesday | 17 | — |
| Thursday | 18 | — |
| Friday | 18 | — |
| Saturday | 17 | — |
| Sunday | 18 | — |
Why it was late
All flights ORD → BOS · Connecting off UA 2331? Check the risk
Questions
How often is UA 2331 from IAD to ORD late?
United Airlines 2331 from Washington, DC to Chicago, IL arrived 15 or more minutes late, was diverted or was cancelled on 21% of 365 scheduled flights between September 2025 and August 2026. 0.8% were cancelled.
How often is UA 2331 from TPA to IAD late?
United Airlines 2331 from Tampa, FL to Washington, DC arrived 15 or more minutes late, was diverted or was cancelled on 8% of 318 scheduled flights between September 2025 and August 2026. 1.3% were cancelled.
How often is UA 2331 from ORD to BOS late?
United Airlines 2331 from Chicago, IL to Boston, MA arrived 15 or more minutes late, was diverted or was cancelled on 48% of 123 scheduled flights between September 2025 and August 2026. 1.6% 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.