Route reliability record
DEN→SBP
Denver to San Luis Obispo
- Flights
- 724
- Period
- September 2025 to August 2026
- Distance
- 931 mi
- Carriers
- 2
This route lands a B+, about a point better than the national rate of 77.3%. About one flight in five arrives 15 minutes late or worse, and those flights are late by a little over an hour on average. That rests on 724 DEN to SBP flights, with a median arrival 4 minutes early.
The US average over the same twelve months is 77.3%, 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
78.5%
Arrivals under 15 minutes late, of 715 completed flights
Avg delay
70 min
Across delayed arrivals only, not all flights
Cancelled
0.28%
National rate is 1.89%
Best carrier
United
78.9% on time across 465 flights
These figures cover 724 flights between September 2025 and August 2026. The median arrival is 4 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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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 |
|---|---|---|---|---|---|
| United Airlines | 465 | 78.9% | 82 min | 0.43% | B+ |
| SkyWest Airlinesthin sample | 259 | 77.6% | 48 min | 0.00% | 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.
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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 flights79.3%
- 2pm–5pm21 flights—
- 5pm–8pm341 flights77.4%
- 8pm–5am—
Scale runs 70% to 85%. Rows with fewer than 30 flights show a dash.
The 11am–2pm window is the strongest at 79.3% on time. The full set of windows spans 2 points.
Explore
Filter DEN to SBP by airline, time, month and day
Pick a breakdown and a carrier. The dashed mark on each row is the same slice for every US flight.
On DEN to SBP, the best departure window is 11am–2pm at 79.3% on time and the worst is 5pm–8pm at 77.4%, a narrow gap of 1.9 points. All US flights leaving 11am–2pm ran 78.3%.
- 5–8am—
- 8–11am—
- 11am–2pm79.3%
- 2–5pm—
- 5–8pm77.4%
- 8pm–5am—
best all US flightsScale 60% to 95%. Cells under 30 flights show a dash.
Across the year
When delays peak on this route
This route's year swings by 30 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.
June is the worst month at 61.7% on time, 30 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, Tuesday is the strongest day at 84.3% on time and Sunday the weakest at 71.8%, a spread of 13 points.
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 11,000 reported delay minutes.
- 37%Late-arriving aircraft
- 35%Carrier
- 15%Extreme weather
- 13%National Airspace System
Extreme weather accounts for 15% 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 2.4 times the usual weather exposure. The split is drawn from 10,707 reported delay minutes.
37% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 11,000 reported delay minutes here, that single category outweighs weather by 3 to one.
Cancellations are rare at 0.28%, 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 stage length
What a delay here actually costs
6.9% 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 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.
The return leg is a different operation and performs like one: it runs 82.2% 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 78.5% 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 five arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 21.5% of the 724 flights in this analysis, against 22.7% 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?
78.5% of flights arrive on time here against a national 77.3%, a difference of about a point in its favour. That is worth a B+ on this site's grading scale.
What time of day has the fewest delays on DEN to SBP?
The 11am–2pm departure window is the strongest at 79.3% on time. The 5pm–8pm window is the weakest at 77.4%, 2 points behind. Later departures inherit delays from earlier flights the same aircraft has already flown, which is why the curve slopes the way it does.
How bad are June delays on DEN to SBP?
June is the weakest month at 61.7% on time, compared with 91.2% in November. Across the year that is 30 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
- United Airlines on DEN to SBP78.9%
- SkyWest Airlines on DEN to SBP77.6%
- DEN to PHX, a related route75.6%
- PHX to SBP, a related route83.5%
- DEN to SLC, a related route78.2%
- United Airlines on-time record78.9%
- SkyWest Airlines on-time record77.6%
- 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, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.