How reliable is Hartsfield Jackson Atlanta International Airport?
Flights from ATL departed within 15 minutes of schedule in 80% of 2,058,665 flights in official BTS history — and weather is calmest in Oct. Here’s the full picture before you book.
Reliability score
on-time, cancellations & delays
Weather favorability
year-round climate
Origin-airport operations
What the departure punctuality at ATL looks like
On-time departures
across 2,058,665 flights
Source: BTS Airport Operations · data through 2026-08-08. Role-specific BTS departure history; advisory context, not a guarantee for any flight.
Weather by month
When the weather works for you at Atlanta
A calm-weather score (0–100) for each month from decades of airport observations — how often conditions disrupt flying, not temperature. Higher is calmer.
Calmest month
Calmest flying weather of the year · 95/100 favorability
Roughest month
Most disruptive — low visibility & fog, thunderstorms · 85/100 favorability
Connecting through ATL
How much layover you really need
Based on 395 sellable domestic itineraries seen through Google Flights. Median observed layover: 100 min.
International transfers add immigration and bag recheck — give yourself this buffer at ATL or more.
Observed windows come from normalized SearchAPI / Google Flights itineraries. They are not official airport MCTs. We score every connecting itinerary against conservative connection floors.
The read on ATL
What the numbers say about flying through Hartsfield Jackson Atlanta International Airport
Across official performance history, flights from Atlanta left within 15 minutes of schedule about 80% of the time over 2,058,665 flights. That's a solid, better-than-average operational record. Pair it with a moderate cancellation rate of 1.5%. When a departure does run late, the typical delay is around 12 minutes.
On weather, Atlanta is an unusually calm-weather airport year-round. October is the calmest stretch for flying, scoring 95 out of 100 for favorable conditions, while December is the most disruptive at 85, driven mainly by low visibility & fog and thunderstorms. The year is relatively steady, so no single month stands out as one to avoid on weather alone.
If you're connecting through ATL, give yourself room. Real itineraries sold through ATL bottom out around 51 minutes for a domestic connection, and international transfer wants roughly 90 minutes once immigration and a bag recheck are in the mix. Those are floors, not comfortable buffers — one inbound delay can erase them, so add margin when the connection matters.
None of this guarantees your specific flight — it’s the backdrop. To turn it into a booking, score real flights to Atlanta, read how we weigh it all in how the PlaneSane Score works, and brush up with how to pick a reliable flight and avoiding weather delays.
Common questions about ATL
- How reliable is Hartsfield Jackson Atlanta International Airport (ATL)?
- Flights from Atlanta left within 15 minutes of schedule roughly 80% of the time across 2,058,665 flights of official history — a solid, better-than-average operational record. The cancellation rate runs about 1.5%. It's advisory context, not a guarantee for any single flight.
- What is the best month to fly from ATL for good weather?
- October has the calmest flying weather at Hartsfield Jackson Atlanta International Airport. December is the most disruptive, mainly from low visibility & fog and thunderstorms.
- How much layover time do you need at ATL?
- Allow at least about 51 minutes for a domestic connection and about 90 minutes for an international one as a floor. These are minimums, not comfortable buffers — a single inbound delay can wipe them out, so add margin when you can.
Reliability guides
Planning a trip through Atlanta?
Score real flights to and from ATL on reliability, weather, and connection safety — not just price.