Flight number record
DL 499
Delta Air Lines · Boston to Denver
- Route
- BOS → DEN
- Departs
- 07:40
- Flights
- 365
- Period
- July 2025 to June 2026
Historical statistics for July 2025 to June 2026, not live status. For today’s DL 499, check with Delta Air Lines.
DL 499 earns a B. More than four flights in five arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 7 points better than the national rate of 77.6%. When something does go wrong the average delay runs roughly 45 minutes. That rests on 365 flights, with a median arrival 6 minutes early.
Set against the rest of the country, DL 499's record is 7 points better than the US average of 77.6%. That gap is worth roughly 71 fewer late arrivals for every thousand flights.
Key figures
On time
84.7%
Arrivals under 15 minutes late, of 359 completed flights
Avg delay
46 min
Across delayed arrivals only, not all flights
Cancelled
1.64%
National rate is 1.81%
1 hour+ late
3.1%
National rate is 8.1%
These figures cover 365 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.
Schedule
When DL 499 flies
DL 499 flies BOS to DEN without a single fixed slot. Its most common scheduled departure was 07:40, used on 95 of 365 flights, with 07:35 (69 flights) and 07:45 (67 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.
- Departs 07:4095 flights26.0%
- Departs 07:3569 flights18.9%
- Departs 07:4567 flights18.4%
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 07:40 departure sits in the 5am–8am window. Across every US flight scheduled in that window the on-time rate is 89.3%, and DL 499 runs 5 points worse at 84.7%. Early departures usually start with an aircraft that has not flown yet that day, which is most of why the window does well.
Against the route
DL 499 next to BOS to DEN
Every carrier on BOS to DEN combined arrived on time 76.5% of the time across 3,899 flights, so DL 499 is 8 points ahead of it. Across its whole network Delta Air Lines managed 81.6%, which this flight beats by 3 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| DL 499 | 365 | 84.7% | 46 min | 1.64% | B |
| All Delta Air Lines on BOS–DEN | 400 | 81.4% | 46 min | 1.75% | B |
| All carriers on BOS–DEN | 3,899 | 76.5% | 58 min | 1.18% | B |
| Delta Air Lines, whole network | 1,038,570 | 81.6% | 71 min | 1.62% | B |
Across the year
DL 499 quarter by quarter
DL 499 did not run the same all year. Its best quarter was Apr–Jun 2026 at 94.4% on time and its weakest Jan–Mar 2026 at 78.2%, a swing of 16 points on roughly 91 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 202592 flights87.8%
- Oct–Dec 202592 flights78.3%
- Jan–Mar 202690 flights78.2%
- Apr–Jun 202691 flights94.4%
Scale runs 70% to 100%. Rows with fewer than 30 flights show a dash.
By weekday, DL 499 ranged from 80.8% on Sunday to 89.8% on Monday. With about 52 flights behind each day, a spread of 9 points is inside normal variation, so the day you fly is not worth changing for this flight.
Delay causes
Why DL 499 runs late
One category carries most of the weight here. National Airspace System accounts for 45% of the 2,536 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.
- 45%National Airspace System
- 39%Carrier
- 15%Late-arriving aircraft
- 1%Extreme weather
The largest share of delay minutes, 39%, 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 981 of the 2,536 delay minutes reported here. The split is drawn from 2,536 delay minutes reported on DL 499.
Cancellations sit at 1.64% against a national 1.81%, which is ordinary. Diversions add another 0.00%.
Connections and routes
What a delay on this flight costs
Badly late arrivals are rare here: only 3.1% land an hour or more behind schedule, against 8.1% 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.
At 1,754 miles this is transcontinental flying, and long routes get a quiet structural advantage. Scheduled block time on a flight this length carries more padding in absolute minutes, so a twenty-minute late departure often still becomes an on-time arrival. Read the on-time rate here as slightly flattering next to a short-haul route with the same operational quality.
DL 499 is not only a BOS to DEN flight. It also flew DEN to BOS (349 flights, 75.2% on time) often enough to be scored on its own. Airlines attach one number to several legs of an aircraft's day, and each leg keeps its own record here, so check which city pair is on your booking before reading a rate.
One caution: this is a thin sample. 365 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.
| Also flown as | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| DEN to BOSthin sample | 349 | 75.2% | 59 min | 1.43% | B |
What to do with this
Booking DL 499
For a booking, read DL 499 as 84.7% on time with 1.64% cancelled over 365 flights. Those are rates from the past twelve months, not a forecast for any particular day.
Related
Where to go next
- BOS to DEN, every carrier and departure
- DEN to BOS, the return direction
- United Airlines 647 on the same route91.1%
- United Airlines 2297 on the same route84.3%
- United Airlines 414 on the same route90.0%
- JetBlue Airways 393 on the same route79.6%
- United Airlines 662 on the same route92.0%
- JetBlue Airways 993 on the same route59.3%
- Boston Logan International (BOS) delay statistics
- Denver International (DEN) delay statistics
- Delta Air Lines on-time record
- Every Delta Air Lines flight number with a record
- The most and least reliable flight numbers in the US
- The best time of day to fly, according to 7.04 million flight records
A flight number here means Delta Air Lines’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.