Flight number record

DL 3100

Delta Air Lines · Atlanta to Birmingham

Route: ATL → BHM
Departs: 08:05
Flights: 341
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 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 14 points better than the national rate of 77.6%. When something does go wrong the average delay runs about 45 minutes. That rests on 341 flights, with a median arrival 11 minutes early.

Set against the rest of the country, DL 3100's record is 14 points better than the US average of 77.6%. That gap is worth roughly 143 fewer late arrivals for every thousand flights.

On time

91.9%

Arrivals under 15 minutes late, of 334 completed flights

Avg delay

46 min

Across delayed arrivals only, not all flights

Cancelled

2.05%

National rate is 1.81%

1 hour+ late

1.8%

National rate is 8.1%

These figures cover 341 flights between July 2025 and June 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.

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 341 flights, with 08:20 (43 flights) and 08:35 (43 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.

Departs 08:0586 flights25.2%
Departs 08:2043 flights12.6%
Departs 08:3543 flights12.6%

Scale runs 0% to 100%. Rows with fewer than 30 flights show a dash.

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 84.1%, and DL 3100 runs 8 points better at 91.9%. Early departures usually start with an aircraft that has not flown yet that day, which is most of why the window does well.

Against the route

DL 3100 next to ATL to BHM

Every carrier on ATL to BHM combined arrived on time 84.0% of the time across 3,306 flights, so DL 3100 is 8 points ahead of it. Across its whole network Delta Air Lines managed 81.6%, which this flight beats by 10 points.

DL 3100 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
DL 3100thin sample	341	91.9%	46 min	2.05%	A
All Delta Air Lines on ATL–BHM	3,306	84.0%	64 min	1.72%	B
All carriers on ATL–BHM	3,306	84.0%	64 min	1.72%	B
Delta Air Lines, whole network	1,038,570	81.6%	71 min	1.62%	B

Across the year

DL 3100 quarter by quarter

Quarter by quarter DL 3100 held fairly steady: 93.6% in Jul–Sep 2025, 89.4% in Oct–Dec 2025, 92.5% in Jan–Mar 2026 and 92.3% in Apr–Jun 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 202579 flights93.6%
Oct–Dec 202587 flights89.4%
Jan–Mar 202684 flights92.5%
Apr–Jun 202691 flights92.3%

Scale runs 80% to 100%. Rows with fewer than 30 flights show a dash.

By weekday, DL 3100 did best on Thursday at 97.9% on time and worst on Monday at 83.7%. Each day rests on about 49 flights, so a gap of 14 points is worth noticing but could still narrow in another year.

Delay causes

Why DL 3100 runs late

One category carries most of the weight here. Carrier accounts for 66% of the 1,231 delay minutes carriers reported, and the remaining four split what is left. The split is by minutes rather than by flights, so a few very long delays count for as much as many short ones.

Carrier
66%
National Airspace System
19%
Late-arriving aircraft
13%
Security
2%

The largest share of delay minutes, 66%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 813 of the 1,231 delay minutes reported here. The split is drawn from 1,231 delay minutes reported on DL 3100.

Cancellations sit at 2.05% against a national 1.81%, 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 8.1% 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 (338 flights, 93.4% 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. 341 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.

Other routes flown as DL 3100
Also flown as	Flights	On time	Avg delay	Cancelled	Grade
BHM to ATLthin sample	338	93.4%	65 min	2.07%	A

What to do with this

Booking DL 3100

For a booking, read DL 3100 as 91.9% on time with 2.05% cancelled over 341 flights. Those are rates from the past twelve months, not a forecast for any particular day.

Where to go next

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, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.

Key figures