ON TIMEBOARD
United Airlines / ATL → IAD

UA 1831 on time

United Airlines 1831: Atlanta to Washington at 2:40 p.m.; Washington to Newark at 5:42 p.m. (past 12 months). Figures below the title are for ATL → IAD, its busiest leg

On time
75%
361 flights · likely 71–80%
Cancelled
0.8%
of scheduled flights
Typical arrival
−4 min
median vs schedule
When late
+97 min
average delay
Similar flights
75%
UA, same route & hour

About 1 in 4 UA 1831 flights from Atlanta arrived 15+ minutes late, diverted or cancelled over the past year (25%); 0.8% were cancelled. The typical flight landed 4 minutes early.

UA 1831: ATL → IAD

Scheduled to leave Atlanta at 2:40 p.m. local time. Over the past year it arrived on time 75% of the time (361 flights), in line with other UA flights on the route at that hour (75%). Last seen in the data Aug 31, 2026.

Month by month

40%70%100%Sep 2025: 70% on time (30 flights)70SepOct 2025: 81% on time (31 flights)81OctNov 2025: 70% on time (30 flights)70NovDec 2025: 69% on time (29 flights)69DecJan 2026: 73% on time (30 flights)73JanFeb 2026: 93% on time (28 flights)93FebMar 2026: 71% on time (31 flights)71MarApr 2026: 83% on time (30 flights)83AprMay 2026: 90% on time (31 flights)90MayJun 2026: 80% on time (30 flights)80JunJul 2026: 48% on time (31 flights)48JulAug 2026: 77% on time (30 flights)77Aug

By day of week

DayFlightsOn time
Monday5381%
Tuesday5283%
Wednesday5275%
Thursday5277%
Friday5169%
Saturday4978%
Sunday5265%

Why it was late

Late inbound plane 47%Air traffic & airport (NAS) 29%Airline (crew, maintenance, ops) 12%Severe weather 12%

All flights ATL → IAD · Connecting off UA 1831? Check the risk

UA 1831: IAD → EWR

Scheduled to leave Washington at 5:42 p.m. local time. Over the past year it arrived on time 55% of the time (210 flights), in line with other UA flights on the route at that hour (54%). Last seen in the data Aug 31, 2026.

Month by month

20%60%100%Dec 2025: too few flights (12 flights)DecJan 2026: too few flights (4 flights)JanFeb 2026: 53% on time (15 flights)53FebMar 2026: 48% on time (29 flights)48MarApr 2026: 70% on time (30 flights)70AprMay 2026: 71% on time (31 flights)71MayJun 2026: 60% on time (30 flights)60JunJul 2026: 32% on time (31 flights)32JulAug 2026: 46% on time (28 flights)46Aug

By day of week

DayFlightsOn time
Monday3250%
Tuesday3057%
Wednesday3053%
Thursday3253%
Friday3256%
Saturday2572%
Sunday2948%

Why it was late

Air traffic & airport (NAS) 40%Severe weather 29%Late inbound plane 19%Airline (crew, maintenance, ops) 12%

All flights IAD → EWR · Connecting off UA 1831? Check the risk

Questions

How often is UA 1831 from ATL to IAD late?

United Airlines 1831 from Atlanta, GA to Washington, DC arrived 15 or more minutes late, was diverted or was cancelled on 25% of 361 scheduled flights between September 2025 and August 2026. 0.8% were cancelled.

How often is UA 1831 from IAD to EWR late?

United Airlines 1831 from Washington, DC to Newark, NJ arrived 15 or more minutes late, was diverted or was cancelled on 45% of 210 scheduled flights between September 2025 and August 2026. 2.9% 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.