Flight number record
DL 816
Delta Air Lines · San Antonio to Boston
- Route
- SAT → BOS
- Departs
- 13:20
- Flights
- 315
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s DL 816, check with Delta Air Lines.
DL 816 draws a D. Roughly one flight in two arrives at least 15 minutes late, and the typical late arrival is an hour and a half behind schedule. Build slack into anything you connect to. That rests on 315 flights, with a median arrival 10 minutes late.
The national on-time rate over the same period is 77.3%, so DL 816 runs 19 points behind the country as a whole. Across a thousand flights that is about 192 extra late arrivals.
Key figures
On time
58.1%
Arrivals under 15 minutes late, of 308 completed flights
Avg delay
85 min
Across delayed arrivals only, not all flights
Cancelled
1.90%
National rate is 1.89%
1 hour+ late
21.4%
National rate is 8.3%
These figures cover 315 flights between September 2025 and August 2026. Beyond the headline rate, 21.4% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Schedule
When DL 816 flies
DL 816 flies SAT to BOS without a single fixed slot. Its most common scheduled departure was 13:20, used on 82 of 315 flights, with 12:22 (36 flights) and 12:25 (33 flights) next.
- Departs 13:2082 flights26.0%
- Departs 12:2236 flights11.4%
- Departs 12:2533 flights10.5%
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 13:20 departure sits in the 11am–2pm window. Across every US flight scheduled in that window the on-time rate is 78.3%, and DL 816 runs 20 points worse at 58.1%. Midday slots inherit some of the morning's delays without yet carrying the full weight of the evening's.
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Against the route
DL 816 next to SAT to BOS
Every carrier on SAT to BOS combined arrived on time 59.7% of the time across 357 flights, so DL 816 is 2 points behind it. Across its whole network Delta Air Lines managed 81.1%, which this flight trails by 23 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| DL 816thin sample | 315 | 58.1% | 85 min | 1.90% | D |
| All Delta Air Lines on SAT–BOSthin sample | 357 | 59.7% | 83 min | 2.24% | D |
| All carriers on SAT–BOSthin sample | 357 | 59.7% | 83 min | 2.24% | D |
| Delta Air Lines, whole network | 1,039,517 | 81.1% | 71 min | 1.74% | B |
Across the year
DL 816 quarter by quarter
DL 816 did not run the same all year. Its best quarter was Jan–Mar 2026 at 71.1% on time and its weakest Jul–Sep 2025 at 23.3%, a swing of 48 points on roughly 63 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 flights23.3%
- Oct–Dec 202577 flights55.3%
- Jan–Mar 202686 flights71.1%
- Apr–Jun 202660 flights64.9%
- Jul–Sep 202662 flights54.8%
Scale runs 15% to 75%.
By weekday, DL 816 did best on Saturday at 75.0% on time and worst on Friday at 46.5%. Each day rests on about 45 flights, so a gap of 29 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late DL 816 runs when it is late
When DL 816 is late it tends to be very late: 66 of its 129 late arrivals were an hour or more behind, and 32 were two hours or more.
- 15+ min early59 flights19.2%
- Within 15 min120 flights39.0%
- 15–29 min late36 flights11.7%
- 30–59 min late27 flights8.8%
- 1–2 hours late34 flights11.0%
- 2+ hours late32 flights10.4%
Scale runs 0% to 100%.
Share of 308 completed flights by arrival against schedule.
Time lost at the gate mostly stays lost. Of 115 departures that left 15 minutes late or more, only 12 made it up before arrival. In the other direction, 26 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 BOS.
The worst days
Worst days for DL 816
The latest arrival of the period was on 6 November 2025, 6 hours 29 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). The five worst days are spread across November, October, March and June, with no single month standing out.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 6 November 2025 | 6 hours 29 minutes | Carrier |
| 13 October 2025 | 4 hours 52 minutes | National Airspace System |
| 11 March 2026 | 4 hours 39 minutes | Late-arriving aircraft |
| 22 June 2026 | 4 hours 18 minutes | Late-arriving aircraft |
| 14 October 2025 | 4 hours 12 minutes | National Airspace System |
Delay causes
Why DL 816 runs late
Late-arriving aircraft accounts for 42% of the 11,000 delay minutes carriers reported here, and the remaining four split what is left.
- 42%Late-arriving aircraft
- 39%National Airspace System
- 15%Carrier
- 3%Extreme weather
42% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 11,000 reported delay minutes here, that single category outweighs weather by 14 to one. The split is drawn from 10,980 delay minutes reported on DL 816.
Cancellations sit at 1.90% against a national 1.89%, which is ordinary. Diversions add another 0.32%.
Connections and routes
What a delay on this flight costs
21.4% of arrivals land a full hour or more behind schedule, against 8.3% nationally. Ninety minutes is the honest minimum for a connection here, and two hours if the onward flight is on a separate ticket.
At 1,764 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.
The same number turns up on three other city pairs in the data, including BOS to SAT (86), MCO to LAX (31) and JAC to SLC (16), but none flew often enough under DL 816 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to SAT to BOS only.
One caution: this is a thin sample. 315 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 DL 816
For a booking, DL 816 is a flight to put a long connection behind. 21.4% of its completed flights arrived an hour or more late, which a short layover will not absorb. If the onward flight is on a separate ticket, the risk sits with you.
Related
Where to go next
- San Antonio International (SAT) delay statistics
- Boston Logan International (BOS) 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.