Flight number record
UA 2634
United Airlines · Atlanta to Washington
- Route
- ATL → IAD
- Departs
- 19:35
- Flights
- 312
- Period
- July 2025 to June 2026
Historical statistics for July 2025 to June 2026, not live status. For today’s UA 2634, check with United Airlines.
UA 2634 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 312 flights, with a median arrival 5 minutes early.
Key figures
On time
76.8%
Arrivals under 15 minutes late, of 311 completed flights
Avg delay
74 min
Across delayed arrivals only, not all flights
Cancelled
0.32%
National rate is 1.81%
1 hour+ late
11.6%
National rate is 8.1%
These figures cover 312 flights between July 2025 and June 2026. Beyond the headline rate, 11.6% 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.
Schedule
When UA 2634 flies
UA 2634 flies ATL to IAD without a single fixed slot. Its most common scheduled departure was 19:35, used on 94 of 312 flights, with 19:32 (76 flights) and 19:34 (32 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.
- Departs 19:3594 flights30.1%
- Departs 19:3276 flights24.4%
- Departs 19:3432 flights10.3%
Scale runs 0% to 100%. Rows with fewer than 30 flights show a dash.
Share of scheduled departures at each local time. Times used on fewer than one flight in ten are not listed.
A 19:35 departure sits in the 5pm–8pm window. Across every US flight scheduled in that window the on-time rate is 68.2%, and UA 2634 runs 9 points better at 76.8%. By that time of day most aircraft have flown several legs already, and whatever went wrong earlier is still in the schedule.
Against the route
UA 2634 next to ATL to IAD
Every carrier on ATL to IAD combined arrived on time 76.5% of the time across 3,979 flights, so UA 2634 is about level with it. United flew 1,099 flights on the same city pair under all its flight numbers, including this one, and those ran 81.4% on time. Across its whole network United Airlines managed 79.0%, which this flight trails by 2 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| UA 2634thin sample | 312 | 76.8% | 74 min | 0.32% | B+ |
| All United Airlines on ATL–IAD | 1,099 | 81.4% | 83 min | 0.55% | B+ |
| All carriers on ATL–IAD | 3,979 | 76.5% | 81 min | 1.99% | B |
| United Airlines, whole network | 821,041 | 79.0% | 72 min | 1.01% | B |
Across the year
UA 2634 quarter by quarter
UA 2634 did not run the same all year. Its best quarter was Oct–Dec 2025 at 88.2% on time and its weakest Jul–Sep 2025 at 68.7%, a swing of 20 points on roughly 78 flights a quarter. The twelve-month rate averages over that, so if you are flying in a weak quarter the quarter's own figure is the better guide.
- Jul–Sep 202583 flights68.7%
- Oct–Dec 202568 flights88.2%
- Jan–Mar 202677 flights81.6%
- Apr–Jun 202684 flights71.4%
Scale runs 60% to 95%. Rows with fewer than 30 flights show a dash.
By weekday, UA 2634 did best on Tuesday at 84.3% on time and worst on Thursday at 66.7%. Each day rests on about 45 flights, so a gap of 18 points is worth noticing but could still narrow in another year.
Delay causes
Why UA 2634 runs late
One category carries most of the weight here. Late-arriving aircraft accounts for 46% of the 5,304 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.
- 46%Late-arriving aircraft
- 27%Carrier
- 26%National Airspace System
- 1%Extreme weather
46% 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 5,304 reported delay minutes here, that single category outweighs weather by 42 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. The split is drawn from 5,304 delay minutes reported on UA 2634.
Cancellations are rare at 0.32%, 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 routes
What a delay on this flight costs
For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 11.6% of arrivals land a full hour or more behind schedule, against 8.1% nationally. A 45-minute layover does not survive that, and no amount of walking quickly changes it. Ninety minutes is the honest minimum here, and two hours if the onward flight is on a separate ticket.
The 534 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 same number turns up on three other city pairs in the data, including ORD to MCO (19), IAD to ORD (2) and IAD to IND (1), but none flew often enough under UA 2634 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to ATL to IAD only.
One caution: this is a thin sample. 312 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 2634
For a booking, read UA 2634 as 76.8% on time with 0.32% cancelled over 312 flights. Those are rates from the past twelve months, not a forecast for any particular day.
Related
Where to go next
- ATL to IAD, every carrier and departure
- IAD to ATL, the return direction
- United Airlines 1831 on the same route77.2%
- Delta Air Lines 2549 on the same route75.0%
- United Airlines 632 on the same route86.3%
- Delta Air Lines 1309 on the same route73.5%
- Frontier Airlines 1082 on the same route58.8%
- Hartsfield-Jackson Atlanta International (ATL) delay statistics
- Washington Dulles International (IAD) 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
- Why the first flight of the morning is statistically safest
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, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.