Flight number record
UA 557
United Airlines · Charleston to Denver
- Route
- CHS → DEN
- Departs
- 16:00
- Flights
- 354
- Period
- July 2025 to June 2026
Historical statistics for July 2025 to June 2026, not live status. For today’s UA 557, check with United Airlines.
UA 557 sits in the middle of the pack with a C+. About seven flights in ten arrive on time by the DOT's definition, 8 points worse than the national rate of 77.6%. The late ones land a little over an hour behind schedule. That rests on 354 flights, with a median arrival right on schedule.
The national on-time rate over the same period is 77.6%, so UA 557 runs 8 points behind the country as a whole. Across a thousand flights that is about 77 extra late arrivals.
Key figures
On time
69.9%
Arrivals under 15 minutes late, of 346 completed flights
Avg delay
70 min
Across delayed arrivals only, not all flights
Cancelled
0.56%
National rate is 1.81%
1 hour+ late
11.8%
National rate is 8.1%
These figures cover 354 flights between July 2025 and June 2026. Beyond the headline rate, 11.8% 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 557 flies
UA 557 flies CHS to DEN without a single fixed slot. Its most common scheduled departure was 16:00, used on 71 of 354 flights, with 16:01 (54 flights) and 16:11 (52 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.
- Departs 16:0071 flights20.1%
- Departs 16:0154 flights15.3%
- Departs 16:1152 flights14.7%
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 16:00 departure sits in the 2pm–5pm window. Across every US flight scheduled in that window the on-time rate is 72.4%, and UA 557 runs 3 points worse at 69.9%. Midday slots inherit some of the morning's delays without yet carrying the full weight of the evening's.
Against the route
UA 557 next to CHS to DEN
Every carrier on CHS to DEN combined arrived on time 69.3% of the time across 644 flights, so UA 557 is about level with it. Across its whole network United Airlines managed 79.0%, which this flight trails by 9 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| UA 557thin sample | 354 | 69.9% | 70 min | 0.56% | C+ |
| All United Airlines on CHS–DEN | 439 | 73.3% | 65 min | 0.68% | C+ |
| All carriers on CHS–DEN | 644 | 69.3% | 58 min | 0.62% | C+ |
| United Airlines, whole network | 821,041 | 79.0% | 72 min | 1.01% | B |
Across the year
UA 557 quarter by quarter
UA 557 did not run the same all year. Its best quarter was Jan–Mar 2026 at 84.1% on time and its weakest Jul–Sep 2025 at 55.7%, a swing of 28 points on roughly 89 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 202592 flights55.7%
- Oct–Dec 202591 flights74.4%
- Jan–Mar 202690 flights84.1%
- Apr–Jun 202681 flights65.0%
Scale runs 45% to 90%. Rows with fewer than 30 flights show a dash.
By weekday, UA 557 did best on Monday at 78.4% on time and worst on Saturday at 63.3%. Each day rests on about 51 flights, so a gap of 15 points is worth noticing but could still narrow in another year.
Delay causes
Why UA 557 runs late
One category carries most of the weight here. National Airspace System accounts for 43% of the 7,224 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.
- 43%National Airspace System
- 33%Late-arriving aircraft
- 21%Carrier
- 3%Extreme weather
43% 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 3,132 minutes out of 7,224, against a national NAS share of 21%. The split is drawn from 7,224 delay minutes reported on UA 557.
Cancellations are rare at 0.56%, below the national 1.81% 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
For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 11.8% 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 1,449 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 three other city pairs in the data, including DEN to HDN (24), DEN to SNA (14) and BIL to DEN (6), but none flew often enough under UA 557 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to CHS to DEN only.
One caution: this is a thin sample. 354 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 557
For a booking, read UA 557 as 69.9% on time with 0.56% cancelled over 354 flights. Those are rates from the past twelve months, not a forecast for any particular day.
Related
Where to go next
- Denver International (DEN) 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.