Flight number record
UA 557
United Airlines · Charleston to Denver
- Route
- CHS → DEN
- Departs
- 16:00
- Flights
- 310
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 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, 5 points worse than the national rate of 77.3%. The late ones land a little over an hour behind schedule. That rests on 310 flights, with a median arrival 1 minute early.
The national on-time rate over the same period is 77.3%, so UA 557 runs 5 points behind the country as a whole. Across a thousand flights that is about 45 extra late arrivals.
Key figures
On time
72.8%
Arrivals under 15 minutes late, of 305 completed flights
Avg delay
72 min
Across delayed arrivals only, not all flights
Cancelled
0.65%
National rate is 1.89%
1 hour+ late
9.8%
National rate is 8.3%
These figures cover 310 flights between September 2025 and August 2026. Beyond the headline rate, 9.8% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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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 310 flights, with 16:01 (54 flights) and 16:11 (52 flights) next.
- Departs 16:0071 flights22.9%
- Departs 16:0154 flights17.4%
- Departs 16:1152 flights16.8%
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 16:00 departure sits in the 2pm–5pm window. Across every US flight scheduled in that window the on-time rate is 71.9%, and UA 557 runs level with that at 72.8%. Midday slots inherit some of the morning's delays without yet carrying the full weight of the evening's.
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Against the route
UA 557 next to CHS to DEN
Every carrier on CHS to DEN combined arrived on time 69.9% of the time across 663 flights, so UA 557 is 3 points ahead of it. Across its whole network United Airlines managed 78.8%, which this flight trails by 6 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| UA 557thin sample | 310 | 72.8% | 72 min | 0.65% | C+ |
| All United Airlines on CHS–DEN | 451 | 74.8% | 71 min | 0.67% | C+ |
| All carriers on CHS–DEN | 663 | 69.9% | 63 min | 0.60% | C+ |
| United Airlines, whole network | 830,825 | 78.8% | 73 min | 1.02% | 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 Apr–Jun 2026 at 65.0%, a swing of 19 points on roughly 78 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 flights66.7%
- Oct–Dec 202591 flights74.4%
- Jan–Mar 202690 flights84.1%
- Apr–Jun 202681 flights65.0%
- Jul–Sep 202618 flights—
Scale runs 55% to 90%. Rows with fewer than 30 flights show a dash.
By weekday, UA 557 did best on Monday at 82.6% on time and worst on Sunday at 62.8%. Each day rests on about 44 flights, so a gap of 20 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late UA 557 runs when it is late
The 83 late arrivals split 28 under half an hour, 25 between 30 and 60 minutes, and 30 an hour or more.
- 15+ min early55 flights18.0%
- Within 15 min167 flights54.8%
- 15–29 min late28 flights9.2%
- 30–59 min late25 flights8.2%
- 1–2 hours late18 flights5.9%
- 2+ hours late12 flights3.9%
Scale runs 0% to 100%.
Share of 305 completed flights by arrival against schedule.
12 of 66 late departures made up the time and arrived on time, 18% of them. In the other direction, 29 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 DEN.
The worst days
Worst days for UA 557
The latest arrival of the period was on 13 April 2026, 5 hours 52 minutes behind schedule; most of its delay minutes were filed as a late-arriving aircraft. The same cause led on three of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 13 April 2026 | 5 hours 52 minutes | Late-arriving aircraft |
| 25 April 2026 | 5 hours 51 minutes | Late-arriving aircraft |
| 31 October 2025 | 5 hours 46 minutes | Carrier |
| 19 December 2025 | 5 hours 32 minutes | Late-arriving aircraft |
| 15 October 2025 | 4 hours 2 minutes | Carrier |
Delay causes
Why UA 557 runs late
Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 5,960 reported delay minutes.
- 37%National Airspace System
- 37%Late-arriving aircraft
- 24%Carrier
- 3%Extreme weather
37% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 5,960 reported delay minutes here, that single category outweighs weather by 15 to one. The split is drawn from 5,960 delay minutes reported on UA 557.
Cancellations are rare at 0.65%, 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
9.8% 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 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.
The same number turns up on four other city pairs in the data, including BIL to DEN (47), DEN to HDN (24) and DEN to SNA (14), 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. 310 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 72.8% on time with 0.65% cancelled over 310 flights. Those are rates from the past twelve months, not a forecast for any particular day.
Related
Where to go next
- Charleston International (CHS) delay statistics
- 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, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.