Route reliability record
DEN→SBP
Denver to San Luis Obispo
- Flights
- 724
- Period
- July 2025 to June 2026
- Distance
- 931 mi
- Carriers
- 2
This route lands a B+, about a point worse than the national rate of 77.6%. About one flight in four arrives 15 minutes late or worse, and those flights are late by a little over an hour on average. That is a workable record, not a spotless one. That rests on 724 DEN to SBP flights, with a median arrival 3 minutes early.
The US average over the same twelve months is 77.6%, so there is little to separate this route from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
76.8%
Arrivals under 15 minutes late, of 715 completed flights
Avg delay
80 min
Across delayed arrivals only, not all flights
Cancelled
0.28%
National rate is 1.81%
Best carrier
United
76.1% on time across 403 flights
These figures cover 724 flights between July 2025 and June 2026. Beyond the headline rate, 8.3% 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.
Carrier by carrier
Which airline is most reliable on DEN to SBP
Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| SkyWest Airlinesthin sample | 321 | 77.6% | 48 min | 0.00% | B+ |
| United Airlines | 403 | 76.1% | 104 min | 0.50% | B+ |
Flight by flight
Flights on DEN to SBP
The flight numbers below flew this route at least 250 times in the period, busiest first. Each has its own record, with its schedule and delay causes.
Departure window
The best time of day to leave
Departure time is the single lever a traveller controls, and it moves the odds more than most people expect. Each bar below is the on-time rate for flights scheduled to leave inside that window, across 724 flights.
- 5am–8am—
- 8am–11am—
- 11am–2pm362 flights76.5%
- 2pm–5pm25 flights—
- 5pm–8pm337 flights76.5%
- 8pm–5am—
Scale runs 70% to 80%. Rows with fewer than 30 flights show a dash.
The 11am–2pm window is the strongest at 76.5% on time. The full set of windows spans half a point.
Across the year
When delays peak on this route
This route's year swings by 36 points from best month to worst, which is wide. An annual average tells you very little about the week you are actually flying, so read the strip rather than the headline if your dates are fixed.
July is the worst month at 54.8% on time, 36 points below November, the best at 91.2%. Summer afternoon convection and peak-season schedules land on the same weeks every year, so this is a pattern you can book around rather than a run of bad luck. January was the busiest month here, with 62 flights.
Across the week, Monday is the strongest day at 82.0% on time and Sunday the weakest at 68.0%. 14 points is a smaller lever than departure hour, but it is free.
Delay causes
Why this route gets delayed
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 13,000 reported delay minutes.
- 36%Late-arriving aircraft
- 29%Carrier
- 20%National Airspace System
- 16%Extreme weather
Extreme weather accounts for 16% 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 monthly strip above is the more useful view of the risk. The national share is 6%, so this operation carries roughly 2.6 times the usual weather exposure. The split is drawn from 13,251 reported delay minutes.
36% 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 2 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.
Cancellations are rare at 0.28%, 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 stage length
What a delay here actually costs
8.3% of arrivals land an hour or more late, close to the national 8.1%. That is the figure that decides a connection, and it says a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last a little over an hour, 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. 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 return leg is a different operation and performs like one: it runs 81.2% on time across 724 flights, 4 points above this direction. Departure banks, aircraft rotations and the congestion at each end all differ, so scoring the two directions together would average away a real 4 points of difference.
One caution: this is a thin sample. 724 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.
Work out the risk of missing a connection in SBP after this flight
What to do with this
Booking this route
Put together: treat all of this as provisional. 724 flights over twelve months is enough to clear this site's floor and not enough to be confident to better than a couple of points. The 76.8% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 715 completed flights over 12 months sit behind that.
Common questions
DEN to SBP questions
How often is DEN to SBP delayed?
About one flight in four arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 23.2% of the 724 flights in this analysis, against 22.4% nationally. Delayed flights are late by a little over an hour on average.
How reliable is DEN to SBP compared with the rest of the country?
76.8% of flights arrive on time here against a national 77.6%, a difference of about a point against it. That is worth a B+ on this site's grading scale.
Does the departure time change the odds on DEN to SBP?
Not by much in this data. Every departure window falls within half a point of the others, so there is no hour worth rearranging a trip for. The overall rate of 76.8% is the figure to plan against.
How bad are July delays on DEN to SBP?
July is the weakest month at 54.8% on time, compared with 91.2% in November. Across the year that is 36 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.
Related
Where to go next
- SBP to DEN — the return legseparate record
- Denver International (DEN) delay statistics
- SkyWest Airlines on DEN to SBP77.6%
- United Airlines on DEN to SBP76.1%
- DEN to PHX, a related route75.7%
- PHX to SBP, a related route83.1%
- DEN to SLC, a related route77.5%
- SkyWest Airlines on-time record77.6%
- United Airlines on-time record76.1%
- Why the first flight of the morning is statistically safest
- Worst months to fly in the US, ranked by the data
Direction matters. DEN to SBP and SBP to DEN are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
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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.