ON TIMEBOARD
United Airlines / IAD → DEN

UA 1587 on time

United Airlines 1587: Washington to Denver at 12:48 p.m.; Denver to Houston at 5:25 p.m. (past 12 months). Figures below the title are for IAD → DEN, its busiest leg

On time
91%
291 flights · likely 88–94%
Cancelled
0.0%
of scheduled flights
Typical arrival
−12 min
median vs schedule
When late
+80 min
average delay
Similar flights
91%
UA, same route & hour

About 1 in 12 UA 1587 flights from Washington arrived 15+ minutes late, diverted or cancelled over the past year (9%); 0.0% were cancelled. The typical flight landed 12 minutes early.

UA 1587: IAD → DEN

Scheduled to leave Washington at 12:48 p.m. local time. Over the past year it arrived on time 91% of the time (291 flights), in line with other UA flights on the route at that hour (91%). Last seen in the data Aug 31, 2026.

Month by month

40%70%100%Aug 2025: 87% on time (31 flights)87AugSep 2025: 97% on time (30 flights)97SepOct 2025: 90% on time (31 flights)90OctNov 2025: 100% on time (30 flights)100NovDec 2025: 93% on time (15 flights)93DecJan 2026: too few flights (5 flights)JanMar 2026: 78% on time (27 flights)78MarApr 2026: 100% on time (30 flights)100AprMay 2026: 94% on time (31 flights)94MayJun 2026: 87% on time (30 flights)87JunJul 2026: 84% on time (31 flights)84JulAug 2026: 90% on time (31 flights)90Aug

By day of week

DayFlightsOn time
Monday4391%
Tuesday4090%
Wednesday4090%
Thursday4293%
Friday4290%
Saturday4293%
Sunday4293%

Why it was late

Late inbound plane 46%Air traffic & airport (NAS) 33%Airline (crew, maintenance, ops) 21%

All flights IAD → DEN · Connecting off UA 1587? Check the risk

UA 1587: DEN → IAH

Scheduled to leave Denver at 5:25 p.m. local time. Over the past year it arrived on time 76% of the time (146 flights), in line with other UA flights on the route at that hour (74%). Last seen in the data Aug 31, 2026.

Month by month

30%65%100%Jan 2026: 81% on time (26 flights)81JanFeb 2026: 82% on time (28 flights)82FebMar 2026: 74% on time (31 flights)74MarApr 2026: 86% on time (29 flights)86AprMay 2026: too few flights (11 flights)MayAug 2026: 43% on time (21 flights)43Aug

By day of week

DayFlightsOn time
Monday2080%
Tuesday2181%
Wednesday2181%
Thursday2181%
Friday2171%
Saturday2167%
Sunday2171%

Why it was late

Air traffic & airport (NAS) 35%Late inbound plane 34%Airline (crew, maintenance, ops) 27%Severe weather 3%

All flights DEN → IAH · Connecting off UA 1587? Check the risk

Questions

How often is UA 1587 from IAD to DEN late?

United Airlines 1587 from Washington, DC to Denver, CO arrived 15 or more minutes late, was diverted or was cancelled on 9% of 291 scheduled flights between September 2025 and August 2026. 0.0% were cancelled.

How often is UA 1587 from DEN to IAH late?

United Airlines 1587 from Denver, CO to Houston, TX arrived 15 or more minutes late, was diverted or was cancelled on 24% of 146 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.