Route reliability record
ATL→BHM
Atlanta to Birmingham
- Flights
- 3,371
- Period
- September 2025 to August 2026
- Distance
- 134 mi
- Carriers
- 1
This route lands a B, 6 points better than the national rate of 77.3%. About one flight in six arrives 15 minutes late or worse, and those flights are late by about an hour on average. That rests on 3,371 ATL to BHM flights, with a median arrival 9 minutes early.
Best time to fly ATL to BHM: a 8am–11am departure, ideally on a Tuesday. Flights in that window arrived on time 91.5% of the time and Tuesday flights 87.2%, against 83.1% for the route overall.
Set against the rest of the country, this route's record is 6 points better than the US average of 77.3%. That gap is worth roughly 58 fewer late arrivals for every thousand flights.
Key figures
On time
83.1%
Arrivals under 15 minutes late, of 3,312 completed flights
Avg delay
64 min
Across delayed arrivals only, not all flights
Cancelled
1.69%
National rate is 1.89%
Best carrier
Delta
83.1% on time across 3,371 flights
These figures cover 3,371 flights between September 2025 and August 2026. The median arrival is 9 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
Which airline is most reliable on ATL to BHM
Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Delta Air Lines | 3,371 | 83.1% | 64 min | 1.69% | B |
Flight by flight
Flights on ATL to BHM
The flight numbers below flew this route at least 250 times in the period, busiest first. Each has its own record, with its schedule and delay causes.
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Departure window
The best time of day to leave
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 15 points, against half a point between the best and worst carrier.
- 5am–8am—
- 8am–11am697 flights91.5%
- 11am–2pm563 flights87.5%
- 2pm–5pm637 flights78.7%
- 5pm–8pm617 flights76.9%
- 8pm–5am857 flights81.3%
Scale runs 70% to 95%. Rows with fewer than 30 flights show a dash.
Book the morning departure. Flights leaving between 8am–11am arrive on time 91.5% of the time, against 76.9% for the evening window. That is 15 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 8pm–5am window is the busiest, with 857 flights scheduled in it.
Explore
Filter ATL to BHM by airline, time, month and day
Pick a breakdown and a carrier. The dashed mark on each row is the same slice for every US flight.
On ATL to BHM, the best departure window is 8am–11am at 91.5% on time and the worst is 5pm–8pm at 76.9%, a wide gap of 14.6 points. All US flights leaving 8am–11am ran 83.9%.
- 5–8am—
- 8–11am91.5%
- 11am–2pm87.5%
- 2–5pm78.7%
- 5–8pm76.9%
- 8pm–5am81.3%
best all US flightsScale 60% to 95%. Cells under 30 flights show a dash.
Across the year
When delays peak on this route
This route's year swings by 20 points from best month to worst, which is wide. An annual average tells you very little about the week you are actually flying, so read the strip rather than the headline if your dates are fixed.
July is the worst month at 71.6% on time, 20 points below September, the best at 91.9%. 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. May was the busiest month here, with 317 flights.
Across the week, Tuesday is the strongest day at 87.2% on time and Sunday the weakest at 79.6%, a spread of 8 points.
Delay causes
Why this route gets delayed
Carrier accounts for 56% of the 36,000 delay minutes carriers reported here, and the remaining four split what is left.
- 56%Carrier
- 26%Late-arriving aircraft
- 13%National Airspace System
- 4%Extreme weather
- 0%Security
The largest share of delay minutes, 56%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 20,000 of the 36,000 delay minutes reported here. The split is drawn from 35,722 reported delay minutes.
Cancellations sit at 1.69% against a national 1.89%, which is ordinary. Diversions add another 0.06%.
Connections and stage length
What a delay here actually costs
5.6% 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 about an hour, which a normal layover absorbs.
At 134 miles this is a short hop, and stage length matters more than it looks. A flight this short spends under two hours in the air, which leaves almost nothing to claw back a late pushback with. Delay here is decided on the ground, in the turn, which is why the 8am–11am window matters as much as it does.
The return leg is a different operation and performs like one: it runs 87.2% on time across 3,371 flights, 4 points above 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 4 points of difference.
The sample behind these figures is 3,371 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.
Work out the risk of missing a connection in BHM after this flight
What to do with this
Booking this route
Put together: the calendar is the biggest lever here, not the carrier or the hour. September runs 91.9% on time and July 71.6%, a swing of 20 points. If the dates move at all, move them out of July before you think about anything else. 3,312 completed flights over 12 months sit behind that.
Common questions
ATL to BHM questions
How often is ATL to BHM delayed?
About one flight in six arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 16.9% of the 3,371 flights in this analysis, against 22.7% nationally. Delayed flights are late by about an hour on average.
How reliable is ATL to BHM compared with the rest of the country?
83.1% of flights arrive on time here against a national 77.3%, a difference of 6 points in its favour. That is worth a B on this site's grading scale.
What time of day has the fewest delays on ATL to BHM?
The 8am–11am departure window is the strongest at 91.5% on time. The 5pm–8pm window is the weakest at 76.9%, 15 points behind. Later departures inherit delays from earlier flights the same aircraft has already flown, which is why the curve slopes the way it does.
How bad are July delays on ATL to BHM?
July is the weakest month at 71.6% on time, compared with 91.9% in September. Across the year that is 20 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.
Related
Where to go next
- BHM to ATL — the return legseparate record
- Hartsfield-Jackson Atlanta International (ATL) delay statistics
- ATL to LGA, a related route72.3%
- DFW to BHM, a related route75.2%
- ATL to MCO, a related route70.3%
- Delta Air Lines on-time record83.1%
- The best time of day to fly, according to 7.05 million flight records
- Worst months to fly in the US, ranked by the data
Direction matters. ATL to BHM and BHM to ATL are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
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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.