Route reliability record
ATL→BUF
Atlanta to Buffalo
- Flights
- 1,508
- Period
- July 2025 to June 2026
- Distance
- 712 mi
- Carriers
- 3
This route lands a B, about a point better than the national rate of 77.6%. About one flight in five arrives 15 minutes late or worse, and those flights are late by about an hour on average. That is a workable record, not a spotless one. That rests on 1,508 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 84.5% of the time and Wednesday flights 85.9%, against 79.0% for the route overall.
The US average over the same twelve months is 77.6%, 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
79.0%
Arrivals under 15 minutes late, of 1,478 completed flights
Avg delay
58 min
Across delayed arrivals only, not all flights
Cancelled
1.92%
National rate is 1.81%
Best carrier
Delta
81.2% on time across 1,250 flights
These figures cover 1,508 flights between July 2025 and June 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.
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 | 1,250 | 81.2% | 51 min | 1.84% | B |
| Frontier Airlinesthin sample | 257 | 68.5% | 81 min | 2.33% | 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.
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 | 79.7% | 81.2% | 1.84% | 8am–11am, Wed | DL 1384 09:00 |
| 2. ATL → ROCAtlanta to Rochester | Delta Air Lines | 75.8% | 77.7% | 2.50% | 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 matters more here than the choice of carrier. The gap between the best and worst window is 10 points, against half a point between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am10 flights—
- 8am–11am531 flights84.5%
- 11am–2pm147 flights74.3%
- 2pm–5pm448 flights75.4%
- 5pm–8pm10 flights—
- 8pm–5am362 flights77.7%
Scale runs 65% to 90%. 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 74.3% on time against 84.5% 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 531 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 24 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.
December is the weak month at 68.0% on time, against 91.9% in September. Winter delays cluster: a single storm system can account for most of a month's shortfall, so an average December hides both very good weeks and genuinely unflyable days. May was the busiest month here, with 149 flights.
Across the week, Wednesday is the strongest day at 85.9% on time and Sunday the weakest at 72.7%. 13 points is a smaller lever than departure hour, but it is free.
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 18,000 reported delay minutes.
- 40%Carrier
- 37%Late-arriving aircraft
- 15%National Airspace System
- 8%Extreme weather
37% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. That is a cascade, and cascades start small and grow through the day. Across 18,000 reported delay minutes here, that single category outweighs weather by 5 to one. It is the strongest argument for booking the first departure of the morning, when the aircraft has been sitting at the gate overnight with nothing to inherit. The split is drawn from 18,062 reported delay minutes.
The largest share of delay minutes, 40%, 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 7,219 of the 18,000 delay minutes reported here.
Cancellations sit at 1.92% against a national 1.81%, which is ordinary. Diversions add another 0.07%.
Connections and stage length
What a delay here actually costs
6.6% of arrivals land an hour or more late, close to the national 8.1%. That is the figure that decides a connection, and it says 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. It is also long enough that the aircraft usually flies three or four legs a day rather than six, which slows how fast delay compounds.
The return leg runs 81.5% on time across 1,507 flights, within 3 points of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.
The sample behind these figures is 1,508 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 December 68.0%, a swing of 24 points. If the dates move at all, move them out of December before you think about anything else. 1,478 completed flights over 12 months sit behind that.
Common questions
ATL to BUF questions
How often is ATL to BUF delayed?
About one flight in five arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 21.0% of the 1,508 flights in this analysis, against 22.4% nationally. Delayed flights are late by about an hour on average.
How reliable is ATL to BUF compared with the rest of the country?
79.0% of flights arrive on time here against a national 77.6%, a difference of about a point 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 BUF?
The 8am–11am departure window is the strongest at 84.5% on time. The 11am–2pm window is the weakest at 74.3%, 10 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 December delays on ATL to BUF?
December is the weakest month at 68.0% on time, compared with 91.9% in September. Across the year that is 24 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 BUF81.2%
- Frontier Airlines on ATL to BUF68.5%
- ATL to LGA, a related route73.4%
- ORD to BUF, a related route70.6%
- ATL to MCO, a related route70.7%
- Delta Air Lines on-time record81.2%
- Frontier Airlines on-time record68.5%
- 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 7.04 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, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.