Carrier route record
DLBOS→ATL
Delta Air Lines · Boston to Atlanta
- Flights
- 3,726
- Period
- September 2025 to August 2026
- Share of route
- 74%
- Carriers
- 4
Historical statistics for September 2025 to August 2026, not live status. For today’s flights, check with Delta Air Lines.
Delta on BOS to ATL lands a B, 4 points better than the national rate of 77.3%. About one flight in five arrives 15 minutes late or worse, and those flights are late by a little over an hour on average. That rests on 3,726 flights. The strongest carrier on the route with a full sample, JetBlue Airways, flew 859 at 66.9% on time.
The US average over the same twelve months is 77.3%, so there is little to separate Delta on BOS to ATL from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
80.8%
Arrivals under 15 minutes late, of 3,651 completed flights
Avg delay
75 min
Across delayed arrivals only, not all flights
Cancelled
1.85%
National rate is 1.89%
Whole route
76.8%
Every carrier on BOS to ATL, 5,050 flights
These figures cover 3,726 flights between September 2025 and August 2026. The median arrival is 10 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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Carrier by carrier
Delta against every carrier on BOS to ATL
Delta flew 3,726 of the 5,050 flights on BOS to ATL, most of the route. Its 80.8% on time is 4 points better than the route as a whole, which runs 76.8%. Ranked by on-time rate it is first of four carriers on the route, where the range runs from Delta at 80.8% to Spirit at 50.0%. One of those carriers flew fewer than 365 flights here, so treat their positions as rough.
The two carriers here are closely matched: 4 points separate the best from the worst. At that spread, schedule and price are better tie-breakers than reliability. Sample sizes are shown so you can see which rows are worth weighing.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Delta Air Lines (this page) | 3,726 | 80.8% | 75 min | 1.85% | B |
| JetBlue Airways | 859 | 66.9% | 70 min | 3.61% | C− |
| Frontier Airlines | 453 | 62.6% | 62 min | 2.87% | D |
| Spirit Airlinesthin sample | 12 | 50.0% | 61 min | 0.00% | F+ |
JetBlue Airways cancels 3.6% of what it schedules here, the highest in the table. A cancelled flight never appears in an on-time rate, so read that column alongside the punctuality one rather than after it.
Flight by flight
Delta flight numbers on BOS to ATL
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Departure window
When Delta runs best on this route
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 19 points, against 4 points between the best and worst carrier.
- 5am–8am725 flights87.4%
- 8am–11am849 flights87.4%
- 11am–2pm614 flights82.1%
- 2pm–5pm650 flights75.1%
- 5pm–8pm686 flights73.7%
- 8pm–5am202 flights68.4%
Scale runs 60% to 95%.
Book the early departure. Flights leaving between 5am–8am arrive on time 87.4% of the time, against 68.4% for the overnight window. That is 19 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 8am–11am window is the busiest, with 849 flights scheduled in it.
Across the year
Delta on BOS to ATL through the year
July is the worst month at 72.8% on time, 14 points below May, the best at 87.0%. Summer afternoon convection and peak-season schedules land on the same weeks every year, so this is a pattern you can book around rather than a run of bad luck. August was the busiest month here, with 353 flights.
Across the week, Wednesday is the strongest day at 89.2% on time and Sunday the weakest at 76.0%, a spread of 13 points.
Arrival by arrival
How late Delta on BOS to ATL runs when it is late
Delta on BOS to ATL often beats the schedule: 1,374 of 3,651 completed flights, 38%, arrived 15 minutes or more early. The 700 late arrivals split 232 under half an hour, 191 between 30 and 60 minutes, and 277 an hour or more.
- 15+ min early1,374 flights37.6%
- Within 15 min1,577 flights43.2%
- 15–29 min late232 flights6.4%
- 30–59 min late191 flights5.2%
- 1–2 hours late164 flights4.5%
- 2+ hours late113 flights3.1%
Scale runs 0% to 100%.
Share of 3,651 completed flights by arrival against schedule.
232 of 780 late departures made up the time and arrived on time, 30% of them. 152 flights left on time and still arrived late.
The worst days
Worst days for Delta on BOS to ATL
The latest arrival of the period was on 26 December 2025, 17 hours 4 minutes behind schedule; most of its delay minutes were filed as a late-arriving aircraft. Three of the five worst days fell in October 2025.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 26 December 2025 | 17 hours 4 minutes | Late-arriving aircraft |
| 30 October 2025 | 14 hours 10 minutes | Carrier |
| 14 August 2026 | 12 hours 21 minutes | Carrier |
| 18 October 2025 | 9 hours 3 minutes | Carrier |
| 6 October 2025 | 8 hours 55 minutes | Carrier |
Delay causes
Why Delta runs late on this route
Late-arriving aircraft accounts for 42% of the 53,000 delay minutes carriers reported here, and the remaining four split what is left.
- 42%Late-arriving aircraft
- 37%Carrier
- 20%National Airspace System
- 1%Extreme weather
42% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 53,000 reported delay minutes here, that single category outweighs weather by 42 to one. The split is drawn from 52,512 reported delay minutes.
The largest share of delay minutes, 37%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 19,000 of the 53,000 delay minutes reported here.
Cancellations sit at 1.85% against a national 1.89%, which is ordinary. Diversions add another 0.16%.
Connections and stage length
What a delay here costs
7.6% of arrivals land an hour or more late, close to the national 8.3%, so a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last a little over an hour, which a normal layover absorbs.
The 946 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.
The return leg is a different operation and performs like one: it runs 74.4% on time across 3,731 flights, 6 points below this direction. Departure banks, aircraft rotations and the congestion at each end all differ, so scoring the two directions together would average away a real 6 points of difference.
The sample behind these figures is 3,726 flights, enough that the headline rate is stable to within roughly a point. The hour-block and month splits divide that further, so read the thinner bars with more caution than the headline.
What to do with this
Booking Delta on BOS to ATL
Put together: the calendar is the biggest lever here, not the carrier or the hour. May runs 87.0% on time and July 72.8%, a swing of 14 points. If the dates move at all, move them out of July before you think about anything else. 3,651 completed flights over 12 months sit behind that.
Related
Where to go next
- BOS to ATL, every carrier
- Delta on ATL to BOS, the return leg
- JetBlue Airways on BOS to ATL66.9%
- Frontier Airlines on BOS to ATL62.6%
- Delta Air Lines network-wide record
- Boston Logan International (BOS) delay statistics
- Hartsfield-Jackson Atlanta International (ATL) delay statistics
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.05 million flight records
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.