Flight number record
UA 2637
United Airlines · Denver to Grand Rapids
- Route
- DEN → GRR
- Departs
- 09:58
- Flights
- 340
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s UA 2637, check with United Airlines.
UA 2637 earns an A+. Close to nine flights in ten arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 11 points better than the national rate of 77.3%. When something does go wrong the average delay runs roughly 40 minutes. That rests on 340 flights, with a median arrival 6 minutes early.
Set against the rest of the country, UA 2637's record is 11 points better than the US average of 77.3%. That gap is worth roughly 109 fewer late arrivals for every thousand flights.
Key figures
On time
88.2%
Arrivals under 15 minutes late, of 339 completed flights
Avg delay
42 min
Across delayed arrivals only, not all flights
Cancelled
0.00%
National rate is 1.89%
1 hour+ late
2.7%
National rate is 8.3%
These figures cover 340 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 2637 flies
UA 2637 flies DEN to GRR without a single fixed slot. Its most common scheduled departure was 09:58, used on 82 of 340 flights, with 09:50 (77 flights) and 10:04 (48 flights) next.
- Departs 09:5882 flights24.1%
- Departs 09:5077 flights22.6%
- Departs 10:0448 flights14.1%
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 09:58 departure sits in the 8am–11am window. Across every US flight scheduled in that window the on-time rate is 83.9%, and UA 2637 runs 4 points better at 88.2%. Early departures usually start with an aircraft that has not flown yet that day, which is most of why the window does well.
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Against the route
UA 2637 next to DEN to GRR
Every carrier on DEN to GRR combined arrived on time 76.5% of the time across 1,235 flights, so UA 2637 is 12 points ahead of it. United flew 727 flights on the same city pair under all its flight numbers, including this one, and those ran 78.3% on time. Across its whole network United Airlines managed 78.8%, which this flight beats by 9 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| UA 2637thin sample | 340 | 88.2% | 42 min | 0.00% | A+ |
| All United Airlines on DEN–GRR | 727 | 78.3% | 56 min | 0.28% | B+ |
| All carriers on DEN–GRR | 1,235 | 76.5% | 52 min | 0.24% | B+ |
| United Airlines, whole network | 830,825 | 78.8% | 73 min | 1.02% | B |
Across the year
UA 2637 quarter by quarter
Quarter by quarter UA 2637 held fairly steady: 88.0% in Oct–Dec 2025, 88.8% in Jan–Mar 2026, 86.8% in Apr–Jun 2026 and 88.5% in Jul–Sep 2026. A spread of 2 points is about what a sample of this size moves on its own, so the annual figure is a fair summary.
- Jul–Sep 20256 flights—
- Oct–Dec 202592 flights88.0%
- Jan–Mar 202689 flights88.8%
- Apr–Jun 202691 flights86.8%
- Jul–Sep 202662 flights88.5%
Scale runs 80% to 95%. Rows with fewer than 30 flights show a dash.
By weekday, UA 2637 did best on Thursday at 95.9% on time and worst on Sunday at 81.6%. Each day rests on about 49 flights, so a gap of 14 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late UA 2637 runs when it is late
The 40 late arrivals split 17 under half an hour, 14 between 30 and 60 minutes, and 9 an hour or more.
- 15+ min early74 flights21.8%
- Within 15 min225 flights66.4%
- 15–29 min late17 flights5.0%
- 30–59 min late14 flights4.1%
- 1–2 hours late7 flights2.1%
- 2+ hours late2 flights0.6%
Scale runs 0% to 100%.
Share of 339 completed flights by arrival against schedule.
9 of 37 late departures made up the time and arrived on time, 24% of them. 12 flights left on time and still arrived late.
The worst days
Worst days for UA 2637
The latest arrival of the period was on 19 December 2025, 2 hours 35 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). The five worst days are spread across December, July, August and May, with no single month standing out.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 19 December 2025 | 2 hours 35 minutes | Carrier |
| 29 July 2026 | 2 hours 32 minutes | Late-arriving aircraft |
| 3 December 2025 | 1 hour 17 minutes | National Airspace System |
| 23 August 2026 | 1 hour 17 minutes | Carrier |
| 3 May 2026 | 1 hour 15 minutes | Late-arriving aircraft |
Delay causes
Why UA 2637 runs late
Carrier accounts for 43% of the 1,683 delay minutes carriers reported here, and the remaining four split what is left.
- 43%Carrier
- 31%Late-arriving aircraft
- 26%National Airspace System
The largest share of delay minutes, 43%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 730 of the 1,683 delay minutes reported here. The split is drawn from 1,683 delay minutes reported on UA 2637.
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
Badly late arrivals are rare here: only 2.7% land an hour or more behind schedule, against 8.3% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.
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 same number turns up on one other city pair in the data, including EGE to DEN (24), but none flew often enough under UA 2637 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to DEN to GRR only.
One caution: this is a thin sample. 340 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 2637
For a booking, UA 2637 has one of the better records a US domestic flight can show: 88.2% on time and 0.00% cancelled. That is a base rate, not a promise about any single day.
Related
Where to go next
- DEN to GRR, every carrier and departure
- GRR to DEN, the return direction
- 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
- Worst months to fly in the US, ranked by the data
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.