Flight number record
UA 308
United Airlines · Philadelphia to Chicago
- Route
- PHL → ORD
- Departs
- 17:00
- Flights
- 297
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s UA 308, check with United Airlines.
UA 308 draws a D+. Roughly one flight in three arrives at least 15 minutes late, and the typical late arrival is an hour and a half behind schedule. Build slack into anything you connect to. That rests on 297 flights, with a median arrival 7 minutes late.
The national on-time rate over the same period is 77.3%, so UA 308 runs 16 points behind the country as a whole. Across a thousand flights that is about 164 extra late arrivals.
Key figures
On time
60.9%
Arrivals under 15 minutes late, of 294 completed flights
Avg delay
96 min
Across delayed arrivals only, not all flights
Cancelled
0.34%
National rate is 1.89%
1 hour+ late
15.3%
National rate is 8.3%
These figures cover 297 flights between September 2025 and August 2026. Beyond the headline rate, 15.3% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Schedule
When UA 308 flies
UA 308 flies PHL to ORD without a single fixed slot. Its most common scheduled departure was 17:00, used on 116 of 297 flights, with 16:59 (32 flights) next.
- Departs 17:00116 flights39.1%
- Departs 16:5932 flights10.8%
Scale runs 0% to 100%.
Share of scheduled departures at each local time. Times used on fewer than one flight in ten are not listed.
A 17:00 departure sits in the 5pm–8pm window. Across every US flight scheduled in that window the on-time rate is 68.0%, and UA 308 runs 7 points worse at 60.9%. By that time of day most aircraft have flown several legs already, and whatever went wrong earlier is still in the schedule.
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Against the route
UA 308 next to PHL to ORD
Every carrier on PHL to ORD combined arrived on time 73.1% of the time across 5,075 flights, so UA 308 is 12 points behind it. United flew 1,846 flights on the same city pair under all its flight numbers, including this one, and those ran 71.9% on time. Across its whole network United Airlines managed 78.8%, which this flight trails by 18 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| UA 308thin sample | 297 | 60.9% | 96 min | 0.34% | D+ |
| All United Airlines on PHL–ORD | 1,846 | 71.9% | 105 min | 2.00% | C |
| All carriers on PHL–ORD | 5,075 | 73.1% | 102 min | 3.59% | C− |
| United Airlines, whole network | 830,825 | 78.8% | 73 min | 1.02% | B |
Across the year
UA 308 quarter by quarter
UA 308 did not run the same all year. Its best quarter was Jan–Mar 2026 at 73.6% on time and its weakest Jul–Sep 2026 at 44.3%, a swing of 29 points on roughly 74 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 202530 flights—
- Oct–Dec 202561 flights57.4%
- Jan–Mar 202653 flights73.6%
- Apr–Jun 202691 flights67.8%
- Jul–Sep 202662 flights44.3%
Scale runs 35% to 80%. Rows with fewer than 30 flights show a dash.
By weekday, UA 308 did best on Monday at 73.2% on time and worst on Sunday at 48.8%. Each day rests on about 42 flights, so a gap of 24 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late UA 308 runs when it is late
The 115 late arrivals split 33 under half an hour, 37 between 30 and 60 minutes, and 45 an hour or more.
- 15+ min early39 flights13.3%
- Within 15 min140 flights47.6%
- 15–29 min late33 flights11.2%
- 30–59 min late37 flights12.6%
- 1–2 hours late15 flights5.1%
- 2+ hours late30 flights10.2%
Scale runs 0% to 100%.
Share of 294 completed flights by arrival against schedule.
Time lost at the gate mostly stays lost. Of 57 departures that left 15 minutes late or more, only 1 made it up before arrival. In the other direction, 59 flights left on time yet arrived 15 minutes late or more, so that delay built up after pushback: in the air, in a holding pattern or on the ground at ORD.
The worst days
Worst days for UA 308
The latest arrival of the period was on 15 March 2026, 19 hours 35 minutes behind schedule; most of its delay minutes were filed as national airspace system delay. The same cause led on five of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 15 March 2026 | 19 hours 35 minutes | National Airspace System |
| 3 July 2026 | 6 hours 59 minutes | National Airspace System |
| 16 August 2026 | 6 hours 57 minutes | National Airspace System |
| 11 June 2026 | 6 hours 14 minutes | National Airspace System |
| 17 June 2026 | 5 hours 32 minutes | National Airspace System |
Delay causes
Why UA 308 runs late
National Airspace System accounts for 71% of the 11,000 delay minutes carriers reported here, and the remaining four split what is left.
- 71%National Airspace System
- 14%Late-arriving aircraft
- 10%Carrier
- 5%Extreme weather
71% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 7,836 minutes out of 11,000, against a national NAS share of 21%. The split is drawn from 11,056 delay minutes reported on UA 308.
Cancellations are rare at 0.34%, below the national 1.89% and low enough to earn the plus on the grade. Roughly one flight in 100 is called off; the risk here is arriving late, not not arriving.
Connections and routes
What a delay on this flight costs
15.3% of arrivals land a full hour or more behind schedule, against 8.3% nationally. Ninety minutes is the honest minimum for a connection here, and two hours if the onward flight is on a separate ticket.
The 678 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.
The same number turns up on six other city pairs in the data, including ORD to SNA (226), ORD to LGA (36) and ORD to ONT (26), but none flew often enough under UA 308 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to PHL to ORD only.
One caution: this is a thin sample. 297 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 308
For a booking, UA 308 is a flight to put a long connection behind. 15.3% of its completed flights arrived an hour or more late, which a short layover will not absorb. If the onward flight is on a separate ticket, the risk sits with you.
Related
Where to go next
- PHL to ORD, every carrier and departure
- ORD to PHL, the return direction
- Philadelphia International (PHL) 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
- How often a connection fails at the major US hubs
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, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.