Flight number record
DL 1509
Delta Air Lines · Houston to Atlanta
- Route
- HOU → ATL
- Departs
- 10:50
- Flights
- 365
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s DL 1509, check with Delta Air Lines.
DL 1509 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 an hour and a half. That rests on 365 flights, with a median arrival 11 minutes early.
Set against the rest of the country, DL 1509's record is 11 points better than the US average of 77.3%. That gap is worth roughly 113 fewer late arrivals for every thousand flights.
Key figures
On time
88.6%
Arrivals under 15 minutes late, of 352 completed flights
Avg delay
86 min
Across delayed arrivals only, not all flights
Cancelled
3.29%
National rate is 1.89%
1 hour+ late
4.5%
National rate is 8.3%
These figures cover 365 flights between September 2025 and August 2026. The median arrival is 11 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 1509 flies
DL 1509 flies HOU to ATL without a single fixed slot. Its most common scheduled departure was 10:50, used on 53 of 365 flights, with 10:40 (46 flights) and 11:09 (38 flights) next.
- Departs 10:5053 flights14.5%
- Departs 10:4046 flights12.6%
- Departs 11:0938 flights10.4%
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 10:50 departure sits in the 8am–11am window. Across every US flight scheduled in that window the on-time rate is 83.9%, and DL 1509 runs 5 points better at 88.6%. 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 1509 next to HOU to ATL
Every carrier on HOU to ATL combined arrived on time 79.2% of the time across 2,850 flights, so DL 1509 is 9 points ahead of it. Delta flew 1,386 flights on the same city pair under all its flight numbers, including this one, and those ran 84.6% on time. Across its whole network Delta Air Lines managed 81.1%, which this flight beats by 8 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| DL 1509 | 365 | 88.6% | 86 min | 3.29% | A− |
| All Delta Air Lines on HOU–ATL | 1,386 | 84.6% | 96 min | 2.09% | B |
| All carriers on HOU–ATL | 2,850 | 79.2% | 66 min | 1.33% | B |
| Delta Air Lines, whole network | 1,039,517 | 81.1% | 71 min | 1.74% | B |
Across the year
DL 1509 quarter by quarter
DL 1509 did not run the same all year. Its best quarter was Jul–Sep 2025 at 100.0% on time and its weakest Jul–Sep 2026 at 83.3%, a swing of 17 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 flights100.0%
- Oct–Dec 202592 flights88.9%
- Jan–Mar 202690 flights87.1%
- Apr–Jun 202691 flights89.7%
- Jul–Sep 202662 flights83.3%
Scale runs 75% to 100%.
By weekday, DL 1509 did best on Monday at 94.1% on time and worst on Saturday at 82.0%. Each day rests on about 52 flights, so a gap of 12 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late DL 1509 runs when it is late
DL 1509 often beats the schedule: 112 of 352 completed flights, 32%, arrived 15 minutes or more early. The 40 late arrivals split 13 under half an hour, 11 between 30 and 60 minutes, and 16 an hour or more.
- 15+ min early112 flights31.8%
- Within 15 min200 flights56.8%
- 15–29 min late13 flights3.7%
- 30–59 min late11 flights3.1%
- 1–2 hours late8 flights2.3%
- 2+ hours late8 flights2.3%
Scale runs 0% to 100%.
Share of 352 completed flights by arrival against schedule.
14 of 52 late departures made up the time and arrived on time, 27% of them. Only 2 left on time and still arrived late.
The worst days
Worst days for DL 1509
The latest arrival of the period was on 14 August 2026, 12 hours 21 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). The same cause led on five of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 14 August 2026 | 12 hours 21 minutes | Carrier |
| 6 June 2026 | 6 hours 32 minutes | Carrier |
| 13 June 2026 | 3 hours 58 minutes | Carrier |
| 10 January 2026 | 2 hours 34 minutes | Carrier |
| 2 February 2026 | 2 hours 34 minutes | Carrier |
Delay causes
Why DL 1509 runs late
Carrier accounts for 57% of the 3,453 delay minutes carriers reported here, and the remaining four split what is left.
- 57%Carrier
- 38%Late-arriving aircraft
- 4%National Airspace System
- 0%Extreme weather
38% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 3,453 reported delay minutes here, that single category outweighs weather by 38 to one. The split is drawn from 3,453 delay minutes reported on DL 1509.
Cancellations run at 3.29%, against 1.89% nationally. That is about one flight in 30 cancelled outright. A cancelled flight is invisible in every on-time figure on this page, so the punctuality numbers above describe only the flights that actually operated.
Connections and routes
What a delay on this flight costs
Badly late arrivals are rare here: only 4.5% 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 696 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.
DL 1509 is not only a HOU to ATL flight. It also flew ATL to HOU (365 flights, 89.5% 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 |
|---|---|---|---|---|---|
| ATL to HOU | 365 | 89.5% | 54 min | 3.56% | A− |
What to do with this
Booking DL 1509
For a booking, the cancellation rate is the figure to plan around on DL 1509: 3.29% of its 365 scheduled flights did not operate. A late arrival costs an hour and a half, but a cancellation costs the day, so leave a later option open.
Related
Where to go next
- HOU to ATL, every carrier and departure
- ATL to HOU, the return direction
- Delta Air Lines 2557 on the same route89.3%
- Delta Air Lines 1195 on the same route79.1%
- William P. Hobby (HOU) delay statistics
- Hartsfield-Jackson Atlanta International (ATL) 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
- Why the first flight of the morning is statistically safest
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.