Carrier route record
UAGRR→DEN
United Airlines · Grand Rapids to Denver
- Flights
- 728
- Period
- July 2025 to June 2026
- Share of route
- 59%
- Carriers
- 4
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with United Airlines.
United on GRR to DEN lands a B+, 2 points better than the national rate of 77.6%. 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 is a workable record, not a spotless one. That rests on 728 flights, with a median arrival 6 minutes early.
The US average over the same twelve months is 77.6%, so there is little to separate United on GRR to DEN from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
79.7%
Arrivals under 15 minutes late, of 720 completed flights
Avg delay
76 min
Across delayed arrivals only, not all flights
Cancelled
0.55%
National rate is 1.81%
Whole route
78.4%
Every carrier on GRR to DEN, 1,238 flights
These figures cover 728 flights between July 2025 and June 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.
Carrier by carrier
United against every carrier on GRR to DEN
United flew 728 of the 1,238 flights on GRR to DEN, most of the route. Its 79.7% on time is about level with the route as a whole at 78.4%. Ranked by on-time rate it is number two of four carriers on the route, where the range runs from SkyWest at 100.0% to Frontier at 74.5%. Three of those carriers flew fewer than 365 flights here, so treat their positions as rough.
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 (this page) | 728 | 79.7% | 76 min | 0.55% | B+ |
| Southwest Airlinesthin sample | 363 | 77.3% | 53 min | 0.28% | B+ |
| Frontier Airlinesthin sample | 146 | 74.5% | 96 min | 0.00% | C+ |
Departure window
When United runs best on this route
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 728 flights.
- 5am–8am—
- 8am–11am365 flights82.6%
- 11am–2pm—
- 2pm–5pm363 flights76.8%
- 5pm–8pm—
- 8pm–5am—
Scale runs 70% to 90%. Rows with fewer than 30 flights show a dash.
The early departures do better, though not dramatically: 82.6% on time for the 8am–11am window against 76.8% for 2pm–5pm. Worth taking if the schedule allows, not worth an extra connection. The 8am–11am window is the busiest, with 365 flights scheduled in it.
Across the year
United on GRR to DEN through the year
January is the weak month at 45.9% on time, against 95.2% 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. January was the busiest month here, with 62 flights.
Across the week, Tuesday is the strongest day at 84.0% on time and Monday the weakest at 75.5%. 9 points is a smaller lever than departure hour, but it is free.
Delay causes
Why United runs late on this route
One category carries most of the weight here. Carrier accounts for 48% of the 11,000 delay minutes carriers reported, and the remaining four split what is left. The split is by minutes rather than by flights, so a few very long delays count for as much as many short ones.
- 48%Carrier
- 30%National Airspace System
- 20%Late-arriving aircraft
- 2%Extreme weather
The largest share of delay minutes, 48%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 5,244 of the 11,000 delay minutes reported here. The split is drawn from 11,028 reported delay minutes.
Cancellations are rare at 0.55%, 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 costs
5.4% 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 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. 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 76.7% on time across 728 flights, 3 points below 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 3 points of difference.
One caution: this is a thin sample. 728 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 United on GRR to DEN
Put together: treat all of this as provisional. 728 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 79.7% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 720 completed flights over 12 months sit behind that.
Related
Where to go next
- GRR to DEN, every carrier
- United on DEN to GRR, the return leg
- Southwest Airlines on GRR to DEN77.3%
- Frontier Airlines on GRR to DEN74.5%
- United Airlines network-wide record
- Denver International (DEN) delay statistics
- Worst months to fly in the US, ranked by the data
- How to read this site: grades, sample sizes, and honest caveats
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.