Flight number record
DL 499
Delta Air Lines · Boston to Denver
- Route
- BOS → DEN
- Departs
- 07:45
- Flights
- 365
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s DL 499, check with Delta Air Lines.
DL 499 lands a B, 6 points better than the national rate of 77.3%. About one flight in six arrives 15 minutes late or worse, and those flights are late by roughly 55 minutes on average. That rests on 365 flights, with a median arrival 7 minutes early.
Set against the rest of the country, DL 499's record is 6 points better than the US average of 77.3%. That gap is worth roughly 63 fewer late arrivals for every thousand flights.
Key figures
On time
83.6%
Arrivals under 15 minutes late, of 360 completed flights
Avg delay
53 min
Across delayed arrivals only, not all flights
Cancelled
1.37%
National rate is 1.89%
1 hour+ late
3.6%
National rate is 8.3%
These figures cover 365 flights between September 2025 and August 2026. The median arrival is 7 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 DL 499 flies
DL 499 flies BOS to DEN without a single fixed slot. Its most common scheduled departure was 07:45, used on 124 of 365 flights, with 07:40 (74 flights) and 07:20 (62 flights) next.
- Departs 07:45124 flights34.0%
- Departs 07:4074 flights20.3%
- Departs 07:2062 flights17.0%
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 07:45 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 6 points worse at 83.6%. 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
DL 499 next to BOS to DEN
Every carrier on BOS to DEN combined arrived on time 75.7% of the time across 3,847 flights, so DL 499 is 8 points ahead of it. Across its whole network Delta Air Lines managed 81.1%, which this flight beats by 3 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| DL 499 | 365 | 83.6% | 53 min | 1.37% | B |
| All Delta Air Lines on BOS–DEN | 365 | 83.6% | 53 min | 1.37% | B |
| All carriers on BOS–DEN | 3,847 | 75.7% | 62 min | 1.38% | B |
| Delta Air Lines, whole network | 1,039,517 | 81.1% | 71 min | 1.74% | 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 73 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 202530 flights80.0%
- Oct–Dec 202592 flights78.3%
- Jan–Mar 202690 flights78.2%
- Apr–Jun 202691 flights94.4%
- Jul–Sep 202662 flights85.2%
Scale runs 70% to 100%.
By weekday, DL 499 did best on Saturday at 90.4% on time and worst on Tuesday at 76.0%. Each day rests on about 52 flights, so a gap of 14 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late DL 499 runs when it is late
DL 499 often beats the schedule: 106 of 360 completed flights, 29%, arrived 15 minutes or more early. The 59 late arrivals split 23 under half an hour, 23 between 30 and 60 minutes, and 13 an hour or more.
- 15+ min early106 flights29.4%
- Within 15 min195 flights54.2%
- 15–29 min late23 flights6.4%
- 30–59 min late23 flights6.4%
- 1–2 hours late9 flights2.5%
- 2+ hours late4 flights1.1%
Scale runs 0% to 100%.
Share of 360 completed flights by arrival against schedule.
8 of 39 late departures made up the time and arrived on time, 21% of them. In the other direction, 28 flights left on time yet arrived 15 minutes late or more, so that delay built up after pushback: in the air, in a holding pattern or on the ground at DEN.
The worst days
Worst days for DL 499
The latest arrival of the period was on 3 August 2026, 5 hours 37 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). Three of the five worst days fell in January 2026.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 3 August 2026 | 5 hours 37 minutes | Carrier |
| 25 January 2026 | 4 hours 25 minutes | Carrier |
| 23 January 2026 | 2 hours 23 minutes | Carrier |
| 19 August 2026 | 2 hours | Carrier |
| 27 January 2026 | 1 hour 57 minutes | Carrier |
Delay causes
Why DL 499 runs late
Carrier accounts for 50% of the 3,147 delay minutes carriers reported here, and the remaining four split what is left.
- 50%Carrier
- 39%National Airspace System
- 11%Late-arriving aircraft
- 1%Extreme weather
The largest share of delay minutes, 50%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 1,564 of the 3,147 delay minutes reported here. The split is drawn from 3,147 delay minutes reported on DL 499.
Cancellations sit at 1.37% against a national 1.89%, 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 3.6% 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.
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, 71.5% 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 | 71.5% | 62 min | 1.15% | C |
What to do with this
Booking DL 499
For a booking, read DL 499 as 83.6% on time with 1.37% 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 414 on the same route89.4%
- United Airlines 647 on the same route90.5%
- United Airlines 2297 on the same route85.1%
- United Airlines 800 on the same route72.9%
- JetBlue Airways 993 on the same route57.2%
- United Airlines 662 on the same route89.3%
- 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
- Worst months to fly in the US, ranked by the data
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, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.