Route reliability record
GRR→DEN
Grand Rapids to Denver
- Flights
- 1,234
- Period
- September 2025 to August 2026
- Distance
- 1,015 mi
- Carriers
- 4
This route lands a B+, about a point worse than the national rate of 77.3%. 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 rests on 1,234 GRR to DEN flights, with a median arrival 5 minutes early.
Best time to fly GRR to DEN: a 5am–8am departure, ideally on a Friday. Flights in that window arrived on time 89.8% of the time and Friday flights 79.9%, against 76.1% for the route overall.
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
76.1%
Arrivals under 15 minutes late, of 1,220 completed flights
Avg delay
75 min
Across delayed arrivals only, not all flights
Cancelled
0.41%
National rate is 1.89%
Best carrier
United
77.6% on time across 727 flights
These figures cover 1,234 flights between September 2025 and August 2026. The median arrival is 5 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 GRR to DEN
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 | 1 | 100.0% | — | 0.00% | A+ |
| United Airlines | 727 | 77.6% | 81 min | 0.55% | B+ |
| Frontier Airlinesthin sample | 147 | 77.2% | 107 min | 0.00% | B+ |
| Southwest Airlinesthin sample | 359 | 72.5% | 56 min | 0.28% | C+ |
Timetable by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
Departure window
The best time of day to leave
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 45 points, against half a point between the best and worst carrier.
- 5am–8am50 flights89.8%
- 8am–11am478 flights82.5%
- 11am–2pm43 flights81.4%
- 2pm–5pm473 flights71.4%
- 5pm–8pm58 flights44.8%
- 8pm–5am132 flights76.2%
Scale runs 35% to 95%.
The 5pm–8pm window is where this operation falls apart: 44.8% on time, against 89.8% for the 5am–8am slot. By evening the aircraft flying these rotations have absorbed a full day of small delays and there is no slack left to recover in. The 8am–11am window is the busiest, with 478 flights scheduled in it.
Explore
Filter GRR to DEN 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 GRR to DEN, the best departure window is 5am–8am at 89.8% on time and the worst is 5pm–8pm at 44.8%, a wide gap of 45.0 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am89.8%
- 8–11am82.5%
- 11am–2pm81.4%
- 2–5pm71.4%
- 5–8pm44.8%
- 8pm–5am76.2%
best all US flightsScale 35% to 95%.
Across the year
When delays peak on this route
This route's year swings by 33 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.
January is the weak month at 57.3% on time, against 90.1% in October. Winter delays cluster: a single storm system can account for most of a month's shortfall, so an average December hides both very good weeks and genuinely unflyable days. August was the busiest month here, with 121 flights.
Across the week, Friday is the strongest day at 79.9% on time and Wednesday the weakest at 71.0%, a spread of 9 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 22,000 reported delay minutes.
- 34%Carrier
- 30%Late-arriving aircraft
- 30%National Airspace System
- 6%Extreme weather
The practical consequence: the 5am–8am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 89.8% on time here. The split is drawn from 21,951 reported delay minutes.
No single cause dominates. carrier at 34%, late-arriving aircraft at 30% and national airspace system at 30% split the 22,000 reported delay minutes between them. An even spread like this usually means the operation is running close to its designed capacity with no one obvious weak point, and it is the hardest pattern for a traveller to route around.
Cancellations are rare at 0.41%, 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
7.4% 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 1,015 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 runs 76.5% on time across 1,235 flights, within half a point of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.
The sample behind these figures is 1,234 flights, enough that the headline rate is stable to within roughly a point. The hour-block and month splits divide that further, so read the thinner bars with more caution than the headline.
Work out the risk of missing a connection in DEN after this flight
What to do with this
Booking this route
Put together: the calendar is the biggest lever here, not the carrier or the hour. October runs 90.1% on time and January 57.3%, a swing of 33 points. If the dates move at all, move them out of January before you think about anything else. 1,220 completed flights over 12 months sit behind that.
Common questions
GRR to DEN questions
How often is GRR to DEN 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 23.9% of the 1,234 flights in this analysis, against 22.7% nationally. Delayed flights are late by a little over an hour on average.
How reliable is GRR to DEN compared with the rest of the country?
76.1% of flights arrive on time here against a national 77.3%, a difference of about a point against it. That is worth a B+ on this site's grading scale.
What time of day has the fewest delays on GRR to DEN?
The 5am–8am departure window is the strongest at 89.8% on time. The 5pm–8pm window is the weakest at 44.8%, 45 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 January delays on GRR to DEN?
January is the weakest month at 57.3% on time, compared with 90.1% in October. Across the year that is 33 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
- DEN to GRR — the return legseparate record
- Denver International (DEN) delay statistics
- United Airlines on GRR to DEN77.6%
- Frontier Airlines on GRR to DEN77.2%
- Southwest Airlines on GRR to DEN72.5%
- GRR to ORD, a related route69.1%
- PHX to DEN, a related route76.7%
- GRR to DTW, a related route79.6%
- SkyWest Airlines on-time record100.0%
- United Airlines on-time record77.6%
- Frontier Airlines on-time record77.2%
- The best time of day to fly, according to 7.05 million flight records
- Worst months to fly in the US, ranked by the data
Direction matters. GRR to DEN and DEN to GRR 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.