Flight number record
UA 1550
United Airlines · Denver to San Luis Obispo
- Route
- DEN → SBP
- Departs
- 19:25
- Flights
- 259
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s UA 1550, check with United Airlines.
UA 1550 earns a B+. More than four flights in five arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 7 points better than the national rate of 77.3%. When something does go wrong the average delay runs an hour and a half. That rests on 259 flights, with a median arrival 6 minutes early.
Set against the rest of the country, UA 1550's record is 7 points better than the US average of 77.3%. That gap is worth roughly 68 fewer late arrivals for every thousand flights.
Key figures
On time
84.1%
Arrivals under 15 minutes late, of 252 completed flights
Avg delay
95 min
Across delayed arrivals only, not all flights
Cancelled
0.00%
National rate is 1.89%
1 hour+ late
7.1%
National rate is 8.3%
These figures cover 259 flights between September 2025 and August 2026. The median arrival is 6 minutes early, which is the part an average hides: most flights here are fine, and the on-time rate is decided by a tail of badly late ones. On-time means under 15 minutes late, the DOT's own threshold.
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Schedule
When UA 1550 flies
UA 1550 flies DEN to SBP without a single fixed slot. Its most common scheduled departure was 19:25, used on 74 of 259 flights, with 19:15 (40 flights) and 19:22 (36 flights) next.
- Departs 19:2574 flights28.6%
- Departs 19:1540 flights15.4%
- Departs 19:2236 flights13.9%
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 19:25 departure sits in the 5pm–8pm window. Across every US flight scheduled in that window the on-time rate is 68.0%, and UA 1550 runs 16 points better at 84.1%. 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 1550 next to DEN to SBP
Every carrier on DEN to SBP combined arrived on time 78.5% of the time across 724 flights, so UA 1550 is 6 points ahead of it. United flew 465 flights on the same city pair under all its flight numbers, including this one, and those ran 78.9% on time. Across its whole network United Airlines managed 78.8%, which this flight beats by 5 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| UA 1550thin sample | 259 | 84.1% | 95 min | 0.00% | B+ |
| All United Airlines on DEN–SBP | 465 | 78.9% | 82 min | 0.43% | B+ |
| All carriers on DEN–SBP | 724 | 78.5% | 70 min | 0.28% | B+ |
| United Airlines, whole network | 830,825 | 78.8% | 73 min | 1.02% | B |
Across the year
UA 1550 quarter by quarter
Quarter by quarter UA 1550 held fairly steady: 87.4% in Oct–Dec 2025, 85.4% in Jan–Mar 2026 and 77.6% in Apr–Jun 2026. A spread of 10 points is about what a sample of this size moves on its own, so the annual figure is a fair summary.
- Jul–Sep 202528 flights—
- Oct–Dec 202591 flights87.4%
- Jan–Mar 202690 flights85.4%
- Apr–Jun 202650 flights77.6%
Scale runs 70% to 95%. Rows with fewer than 30 flights show a dash.
By weekday, UA 1550 did best on Wednesday at 91.9% on time and worst on Sunday at 66.7%. Each day rests on about 37 flights, so a gap of 25 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late UA 1550 runs when it is late
UA 1550 often beats the schedule: 83 of 252 completed flights, 33%, arrived 15 minutes or more early. The 40 late arrivals split 9 under half an hour, 13 between 30 and 60 minutes, and 18 an hour or more.
- 15+ min early83 flights32.9%
- Within 15 min129 flights51.2%
- 15–29 min late9 flights3.6%
- 30–59 min late13 flights5.2%
- 1–2 hours late12 flights4.8%
- 2+ hours late6 flights2.4%
Scale runs 0% to 100%.
Share of 252 completed flights by arrival against schedule.
A late pushback is often recovered here: of 52 departures that left 15 minutes late or more, 16 still arrived on time. Only 4 left on time and still arrived late.
The worst days
Worst days for UA 1550
The latest arrival of the period was on 11 November 2025, 12 hours 14 minutes behind schedule; most of its delay minutes were filed as extreme weather. On three of the five worst days the largest share was filed as a late-arriving aircraft.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 11 November 2025 | 12 hours 14 minutes | Extreme weather |
| 13 December 2025 | 11 hours 1 minute | Extreme weather |
| 17 December 2025 | 3 hours 29 minutes | Late-arriving aircraft |
| 17 February 2026 | 3 hours 16 minutes | Late-arriving aircraft |
| 30 November 2025 | 2 hours 22 minutes | Late-arriving aircraft |
Delay causes
Why UA 1550 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 3,805 reported delay minutes.
- 41%Late-arriving aircraft
- 37%Extreme weather
- 17%Carrier
- 5%National Airspace System
Extreme weather accounts for 37% of delay minutes, well above the single-digit share typical across the system. Weather delays are lumpy: they arrive as whole bad days rather than as a steady drag, so the quarterly figures above are the more useful view of the risk. The national share is 6%, so this operation carries roughly 6.2 times the usual weather exposure. The split is drawn from 3,805 delay minutes reported on UA 1550.
Cancellations are rare at 0.00%, below the national 1.89% and low enough to earn the plus on the grade. Almost no flights are called off; the risk here is arriving late, not not arriving.
Connections and routes
What a delay on this flight costs
7.1% of arrivals land an hour or more late, close to the national 8.3%, so a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last an hour and a half, which a normal layover absorbs.
The 931 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 ORD to BWI (35), DTW to SFO (29) and SFO to IND (21), but none flew often enough under UA 1550 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to DEN to SBP only.
One caution: this is a thin sample. 259 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 1550
For a booking, read UA 1550 as 84.1% on time with 0.00% cancelled over 259 flights. Those are rates from the past twelve months, not a forecast for any particular day.
Related
Where to go next
- DEN to SBP, every carrier and departure
- SBP to DEN, the return direction
- SkyWest Airlines 4765 on the same route77.6%
- 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.