Route reliability record
ATL→BUF
Atlanta to Buffalo
- Flights
- 1,534
- Period
- September 2025 to August 2026
- Distance
- 712 mi
- Carriers
- 3
This route lands a B, level with the national rate of 77.3%. Roughly one flight in four arrives 15 minutes late or worse, and those flights are late by about an hour on average. That rests on 1,534 ATL to BUF flights, with a median arrival 3 minutes early.
Best time to fly ATL to BUF: a 8am–11am departure, ideally on a Wednesday. Flights in that window arrived on time 81.8% of the time and Wednesday flights 86.1%, against 76.9% for the route overall.
The US average over the same twelve months is 77.3%, so there is little to separate this route from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
76.9%
Arrivals under 15 minutes late, of 1,504 completed flights
Avg delay
63 min
Across delayed arrivals only, not all flights
Cancelled
1.89%
National rate is 1.89%
Best carrier
Delta
79.1% on time across 1,255 flights
These figures cover 1,534 flights between September 2025 and August 2026. The median arrival is 3 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 BUF
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 | 1,255 | 79.1% | 55 min | 1.75% | B |
| Frontier Airlinesthin sample | 278 | 67.2% | 84 min | 2.52% | C |
| Southwest Airlinesthin sample | 1 | 0.0% | 92 min | 0.00% | F+ |
Flight by flight
Flights on ATL to BUF
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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Best ways to make this trip
The most reliable ways to fly Atlanta to Buffalo
Every airline on this route and on the routes between nearby airports, ranked by how often a scheduled flight actually operated and arrived on time. 1 of the top 2 use a different airport at one end.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. ATL → BUFAtlanta to Buffalo | Delta Air Lines | 77.7% | 79.1% | 1.75% | 8am–11am, Wed | DL 1384 09:00 |
| 2. ATL → ROCAtlanta to Rochester | Delta Air Lines | 76.1% | 77.8% | 2.21% | 8am–11am, Wed | DL 2511 09:48 |
Success is the share of scheduled flights that operated and arrived less than 15 minutes late, so a cancelled flight counts against it. “(route)” means the best time comes from every carrier on the route rather than this airline alone.
Departure window
The best time of day to leave
Departure time is the single lever a traveller controls, and it moves the odds more than most people expect. Each bar below is the on-time rate for flights scheduled to leave inside that window, across 1,534 flights.
- 5am–8am10 flights—
- 8am–11am541 flights81.8%
- 11am–2pm173 flights73.2%
- 2pm–5pm440 flights74.9%
- 5pm–8pm7 flights—
- 8pm–5am363 flights73.9%
Scale runs 65% to 85%. Rows with fewer than 30 flights show a dash.
The weak window here is the middle of the day, not the evening: 11am–2pm runs 73.2% on time against 81.8% for 8am–11am. That shape usually means a departure bank rather than an accumulating delay, so the recovery later in the afternoon is real rather than noise. The 8am–11am window is the busiest, with 541 flights scheduled in it.
Explore
Filter ATL to BUF 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 BUF, the best departure window is 8am–11am at 81.8% on time and the worst is 11am–2pm at 73.2%, a real gap of 8.6 points. All US flights leaving 8am–11am ran 83.9%.
- 5–8am—
- 8–11am81.8%
- 11am–2pm73.2%
- 2–5pm74.9%
- 5–8pm—
- 8pm–5am73.9%
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 40 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 52.4% on time, 40 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 149 flights.
Across the week, Wednesday is the strongest day at 86.1% on time and Saturday the weakest at 72.0%, a spread of 14 points.
Delay causes
Why this route gets delayed
Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 22,000 reported delay minutes.
- 41%Late-arriving aircraft
- 38%Carrier
- 15%National Airspace System
- 6%Extreme weather
41% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 22,000 reported delay minutes here, that single category outweighs weather by 7 to one. The split is drawn from 21,710 reported delay minutes.
The largest share of delay minutes, 38%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 8,267 of the 22,000 delay minutes reported here.
Cancellations sit at 1.89% against a national 1.89%, which is ordinary. Diversions add another 0.07%.
Connections and stage length
What a delay here actually costs
7.8% 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.
The 712 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 80.4% on time across 1,533 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 1,534 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 BUF 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 52.4%, a swing of 40 points. If the dates move at all, move them out of July before you think about anything else. 1,504 completed flights over 12 months sit behind that.
Common questions
ATL to BUF questions
How often is ATL to BUF delayed?
Roughly one flight in four arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 23.1% of the 1,534 flights in this analysis, against 22.7% nationally. Delayed flights are late by about an hour on average.
How reliable is ATL to BUF compared with the rest of the country?
76.9% of flights arrive on time here against a national 77.3%, a difference of half a point against it. That is worth a B on this site's grading scale.
What time of day has the fewest delays on ATL to BUF?
The 8am–11am departure window is the strongest at 81.8% on time. The 11am–2pm window is the weakest at 73.2%, 9 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 BUF?
July is the weakest month at 52.4% on time, compared with 91.9% in September. Across the year that is 40 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
- BUF to ATL — the return legseparate record
- Hartsfield-Jackson Atlanta International (ATL) delay statistics
- Delta Air Lines on ATL to BUF79.1%
- Frontier Airlines on ATL to BUF67.2%
- ATL to LGA, a related route72.3%
- ORD to BUF, a related route70.4%
- ATL to MCO, a related route70.3%
- Delta Air Lines on-time record79.1%
- Frontier Airlines on-time record67.2%
- Southwest Airlines on-time record0.0%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.05 million flight records
Direction matters. ATL to BUF and BUF 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.