Flight number record
UA 1015
United Airlines · Boston to Chicago
- Route
- BOS → ORD
- Departs
- 18:23
- Flights
- 302
- Period
- July 2025 to June 2026
Historical statistics for July 2025 to June 2026, not live status. For today’s UA 1015, check with United Airlines.
UA 1015 earns an F−, which is as low as this site's scale goes for a reason. Only 48.8% of flights arrive inside the 15-minute window, 29 points worse than the national rate of 77.6%. Late arrivals average an hour and a half. Treat any tight connection here as a coin flip. That rests on 302 flights, with a median arrival 16 minutes late.
The national on-time rate over the same period is 77.6%, so UA 1015 runs 29 points behind the country as a whole. Across a thousand flights that is about 288 extra late arrivals.
Key figures
On time
48.8%
Arrivals under 15 minutes late, of 289 completed flights
Avg delay
90 min
Across delayed arrivals only, not all flights
Cancelled
3.97%
National rate is 1.81%
1 hour+ late
23.9%
National rate is 8.1%
These figures cover 302 flights between July 2025 and June 2026. Beyond the headline rate, 23.9% of arrivals land a full hour or more behind schedule. That is the number that wrecks a connection, and it is not visible in an on-time percentage alone.
Schedule
When UA 1015 flies
UA 1015 flies BOS to ORD without a single fixed slot. Its most common scheduled departure was 18:23, used on 76 of 302 flights, with 18:03 (48 flights) and 18:40 (33 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.
- Departs 18:2376 flights25.2%
- Departs 18:0348 flights15.9%
- Departs 18:4033 flights10.9%
Scale runs 0% to 100%. Rows with fewer than 30 flights show a dash.
Share of scheduled departures at each local time. Times used on fewer than one flight in ten are not listed.
A 18:23 departure sits in the 5pm–8pm window. Across every US flight scheduled in that window the on-time rate is 68.2%, and UA 1015 runs 19 points worse at 48.8%. By that time of day most aircraft have flown several legs already, and whatever went wrong earlier is still in the schedule.
Against the route
UA 1015 next to BOS to ORD
Every carrier on BOS to ORD combined arrived on time 72.7% of the time across 7,637 flights, so UA 1015 is 24 points behind it. United flew 2,678 flights on the same city pair under all its flight numbers, including this one, and those ran 75.0% on time. Across its whole network United Airlines managed 79.0%, which this flight trails by 30 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| UA 1015thin sample | 302 | 48.8% | 90 min | 3.97% | F− |
| All United Airlines on BOS–ORD | 2,678 | 75.0% | 85 min | 1.90% | B |
| All carriers on BOS–ORD | 7,637 | 72.7% | 84 min | 2.91% | C |
| United Airlines, whole network | 821,041 | 79.0% | 72 min | 1.01% | B |
Across the year
UA 1015 quarter by quarter
UA 1015 did not run the same all year. Its best quarter was Apr–Jun 2026 at 59.5% on time and its weakest Jul–Sep 2025 at 34.6%, a swing of 25 points on roughly 76 flights a quarter. The twelve-month rate averages over that, so if you are flying in a weak quarter the quarter's own figure is the better guide.
- Jul–Sep 202585 flights34.6%
- Oct–Dec 202589 flights48.2%
- Jan–Mar 202653 flights57.1%
- Apr–Jun 202675 flights59.5%
Scale runs 25% to 65%. Rows with fewer than 30 flights show a dash.
By weekday, UA 1015 did best on Wednesday at 54.8% on time and worst on Sunday at 37.5%. Each day rests on about 43 flights, so a gap of 17 points is worth noticing but could still narrow in another year.
Delay causes
Why UA 1015 runs late
One category carries most of the weight here. Late-arriving aircraft accounts for 51% of the 13,000 delay minutes carriers reported, and the remaining four split what is left. The split is by minutes rather than by flights, so a few very long delays count for as much as many short ones.
- 51%Late-arriving aircraft
- 35%National Airspace System
- 11%Carrier
- 3%Extreme weather
51% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. That is a cascade, and cascades start small and grow through the day. Across 13,000 reported delay minutes here, that single category outweighs weather by 17 to one. It is the strongest argument for booking the first departure of the morning, when the aircraft has been sitting at the gate overnight with nothing to inherit. The split is drawn from 13,284 delay minutes reported on UA 1015.
Cancellations run at 3.97%, against 1.81% nationally. That is about one flight in 25 cancelled outright. A cancelled flight is invisible in every on-time figure on this page, so the punctuality numbers above describe only the flights that actually operated.
Connections and routes
What a delay on this flight costs
For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 23.9% of arrivals land a full hour or more behind schedule, against 8.1% nationally. A 45-minute layover does not survive that, and no amount of walking quickly changes it. Ninety minutes is the honest minimum here, and two hours if the onward flight is on a separate ticket.
The 867 miles between these two airports put this in the middle of the US network, around two and a half to three hours of block time. That is enough cruise to absorb a ten-minute late pushback and not enough to absorb thirty. It is also long enough that the aircraft usually flies three or four legs a day rather than six, which slows how fast delay compounds.
The same number turns up on ten other city pairs in the data, including SFO to BOS (59), ORD to IAD (35) and ORD to DEN (16), but none flew often enough under UA 1015 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to BOS to ORD only.
One caution: this is a thin sample. 302 flights over twelve months is enough to clear this site's floor but not enough to pin the rate down tightly, and a single bad week moves it by more than a point. Treat the grade as a rough reading.
What to do with this
Booking UA 1015
For a booking, the cancellation rate is the figure to plan around on UA 1015: 3.97% of its 302 scheduled flights did not operate. A late arrival costs an hour and a half, but a cancellation costs the day, so leave a later option open.
Related
Where to go next
- BOS to ORD, every carrier and departure
- ORD to BOS, the return direction
- United Airlines 2040 on the same route52.3%
- United Airlines 1732 on the same route84.5%
- United Airlines 1414 on the same route94.2%
- JetBlue Airways 311 on the same route84.3%
- Delta Air Lines 2646 on the same route60.3%
- Delta Air Lines 2570 on the same route80.0%
- Boston Logan International (BOS) delay statistics
- Chicago O'Hare International (ORD) delay statistics
- United Airlines on-time record
- Every United Airlines flight number with a record
- The most and least reliable flight numbers in the US
- Why the first flight of the morning is statistically safest
A flight number here means United Airlines’s own number as it reports to the DOT. How the figures are computed is on the methodology page.
Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.