Flight number record
DL 3100
Delta Air Lines · Atlanta to Birmingham
- Route
- ATL → BHM
- Departs
- 08:05
- Flights
- 346
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s DL 3100, check with Delta Air Lines.
DL 3100 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 15 points better than the national rate of 77.3%. When something does go wrong the average delay runs about an hour. That rests on 346 flights, with a median arrival 11 minutes early.
Set against the rest of the country, DL 3100's record is 15 points better than the US average of 77.3%. That gap is worth roughly 148 fewer late arrivals for every thousand flights.
Key figures
On time
92.1%
Arrivals under 15 minutes late, of 340 completed flights
Avg delay
55 min
Across delayed arrivals only, not all flights
Cancelled
1.73%
National rate is 1.89%
1 hour+ late
1.8%
National rate is 8.3%
These figures cover 346 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 3100 flies
DL 3100 flies ATL to BHM without a single fixed slot. Its most common scheduled departure was 08:05, used on 86 of 346 flights, with 08:20 (47 flights) next.
- Departs 08:0586 flights24.9%
- Departs 08:2047 flights13.6%
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 08:05 departure sits in the 8am–11am window. Across every US flight scheduled in that window the on-time rate is 83.9%, and DL 3100 runs 8 points better at 92.1%. 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 3100 next to ATL to BHM
Every carrier on ATL to BHM combined arrived on time 83.1% of the time across 3,371 flights, so DL 3100 is 9 points ahead of it. Across its whole network Delta Air Lines managed 81.1%, which this flight beats by 11 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| DL 3100thin sample | 346 | 92.1% | 55 min | 1.73% | A |
| All Delta Air Lines on ATL–BHM | 3,371 | 83.1% | 64 min | 1.69% | B |
| All carriers on ATL–BHM | 3,371 | 83.1% | 64 min | 1.69% | B |
| Delta Air Lines, whole network | 1,039,517 | 81.1% | 71 min | 1.74% | B |
Across the year
DL 3100 quarter by quarter
Quarter by quarter DL 3100 held fairly steady: 89.4% in Oct–Dec 2025, 92.5% in Jan–Mar 2026, 92.3% in Apr–Jun 2026 and 93.5% in Jul–Sep 2026. A spread of 4 points is about what a sample of this size moves on its own, so the annual figure is a fair summary.
- Jul–Sep 202522 flights—
- Oct–Dec 202587 flights89.4%
- Jan–Mar 202684 flights92.5%
- Apr–Jun 202691 flights92.3%
- Jul–Sep 202662 flights93.5%
Scale runs 80% to 100%. Rows with fewer than 30 flights show a dash.
By weekday, DL 3100 ranged from 86.3% on Monday to 98.0% on Thursday. With about 49 flights behind each day, a spread of 12 points is inside normal variation, so the day you fly is not worth changing for this flight.
Arrival by arrival
How late DL 3100 runs when it is late
DL 3100 often beats the schedule: 96 of 340 completed flights, 28%, arrived 15 minutes or more early. The 27 late arrivals split 11 under half an hour, 10 between 30 and 60 minutes, and 6 an hour or more.
- 15+ min early96 flights28.2%
- Within 15 min217 flights63.8%
- 15–29 min late11 flights3.2%
- 30–59 min late10 flights2.9%
- 1–2 hours late5 flights1.5%
- 2+ hours late1 flights0.3%
Scale runs 0% to 100%.
Share of 340 completed flights by arrival against schedule.
6 of 27 late departures made up the time and arrived on time, 22% of them. Only 6 left on time and still arrived late.
The worst days
Worst days for DL 3100
The latest arrival of the period was on 2 August 2026, 6 hours 30 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 |
|---|---|---|
| 2 August 2026 | 6 hours 30 minutes | Carrier |
| 3 May 2026 | 1 hour 42 minutes | Carrier |
| 29 September 2025 | 1 hour 28 minutes | Carrier |
| 14 November 2025 | 1 hour 18 minutes | Carrier |
| 15 June 2026 | 1 hour 12 minutes | Carrier |
Delay causes
Why DL 3100 runs late
Carrier accounts for 70% of the 1,488 delay minutes carriers reported here, and the remaining four split what is left.
- 70%Carrier
- 19%National Airspace System
- 10%Late-arriving aircraft
- 2%Security
The largest share of delay minutes, 70%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 1,041 of the 1,488 delay minutes reported here. The split is drawn from 1,488 delay minutes reported on DL 3100.
Cancellations sit at 1.73% 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 1.8% 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.
DL 3100 is not only a ATL to BHM flight. It also flew BHM to ATL (343 flights, 93.8% 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. 346 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 |
|---|---|---|---|---|---|
| BHM to ATLthin sample | 343 | 93.8% | 84 min | 1.75% | A |
What to do with this
Booking DL 3100
For a booking, read DL 3100 as 92.1% on time with 1.73% cancelled over 346 flights. Those are rates from the past twelve months, not a forecast for any particular day.
Related
Where to go next
- ATL to BHM, every carrier and departure
- BHM to ATL, the return direction
- Delta Air Lines 3012 on the same route86.8%
- Delta Air Lines 2484 on the same route79.2%
- Delta Air Lines 2034 on the same route80.1%
- Delta Air Lines 3164 on the same route89.8%
- 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
- How to read this site: grades, sample sizes, and honest caveats
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.