Best Time to Fly — On-Time Rates by Hour and Airport

Folk wisdom says take the first flight out. Here is what the filings say, one airport at a time: the share of departures that actually left on time in each part of the day, every day of the week, over the three years through June 2026. These are historical odds, not forecasts. The records say what happened on this schedule over three years; they know nothing about tomorrow’s thunderstorm.

Data through June 2026 · Bureau of Transportation Statistics

Every airport in the filings is on this list; the quiet ones say so instead of printing a rate. The board below changes with the picker.

Hartsfield Jackson Atlanta ATL

Mornings out of ATL left on time 86% of the time; after 6pm, 72%.

335,217 departures between 6am and noon, 301,200 after 6pm — July 2023 through June 2026.

Departures that left on time, by hour and weekday

Share of departures that left on time, by hour band and day of week.
Departure time MonTueWedThuFriSatSun
Before 6am 87 88 88 89 86 86 84
6–8am 88 91 91 91 89 88 88
8–10am 85 89 90 88 87 87 86
10am–12pm 81 86 87 85 83 82 82
12–2pm 81 85 86 84 81 81 79
2–4pm 76 80 82 78 76 78 73
4–6pm 73 77 79 74 73 74 68
6–8pm 70 76 77 69 69 73 65
8–10pm 71 77 78 70 70 74 65
10pm–12am 73 81 82 72 71 79 66
fewer left on time more left on time

Everything else about ATL — months, airlines, delay causes

How to read the grid

Each square is one hour band on one weekday, pooled across the three years in the window. The number is the share of departures scheduled in that band that pushed back within 15 minutes. Greener squares had more departures leave on time; amber squares had fewer. The scale is pinned to the same range for every airport, so a green square at one airport means what a green square means at the next one.

A dash means fewer than 100 departures fell in that square across the whole window — too thin to rate, so it is left blank. Everything here is departures: the moment the aircraft leaves the gate, not the moment it lands.

The other tools

  • Route reliability — An origin and a destination, then the route’s record airline by airline — how often flights arrived on time, how late they ran when they did not, and the months to avoid.
  • Airline comparison — Every reporting carrier side by side: arrival on-time rate, cancellation rate, and what the delay minutes were put down to.
  • Connection risk — A layover length and an arrival airport: what share of historical arrivals would have made that connection.

Questions travelers ask

Is the early flight really more reliable?
Usually, and by more than most travelers expect. Delays pile up through the day as aircraft and crews fall behind their schedules, so the first departures of the morning start from a clean board while the evening ones inherit whatever went wrong earlier. The grid above shows how wide that gap is at the airport you picked — at some it is a few points, at others it is twenty.
What counts as leaving on time?
The Bureau of Transportation Statistics counts a departure as on time when the aircraft pushes back less than 15 minutes after its scheduled time. Flights that were cancelled never departed, so they are not counted as late departures; cancellations are reported separately on each airport page.
Why do some squares show a dash instead of a number?
Because fewer than 100 departures fell in that hour band on that weekday across the whole window. A rate built on a handful of flights looks precise and means nothing, so the square stays blank rather than pretending.
Does this tell me whether my flight will be late?
No. Every number here is a record of what already happened, July 2023 through June 2026. The weather on the day, an aircraft that never arrived from its last leg, and a hundred other things decide your departure. What the record can do is tell you which hours at this airport have historically given travelers the better starting position.