Route reliability record
ATL→SLC
Atlanta to Salt Lake City
- Flights
- 2,965
- Period
- July 2025 to June 2026
- Distance
- 1,590 mi
- Carriers
- 2
This route lands a B+, 5 points better than the national rate of 77.6%. About one flight in six arrive 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 2,965 flights, with a median arrival 6 minutes early.
Set against the rest of the country, this route's record is 5 points better than the US average of 77.6%. That gap is worth roughly 54 fewer late arrivals for every thousand flights.
Key figures
On time
83.0%
Arrivals under 15 minutes late, of 2,947 completed flights
Avg delay
60 min
Across delayed arrivals only, not all flights
Cancelled
0.40%
National rate is 1.81%
Best carrier
Delta
83.0% on time across 2,959 flights
These figures cover 2,965 flights between July 2025 and June 2026. The median arrival is 6 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 SLC
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 | 2,959 | 83.0% | 60 min | 0.41% | B+ |
| Frontier Airlinesthin sample | 6 | 66.7% | 70 min | 0.00% | C+ |
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. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am22 flights—
- 8am–11am737 flights89.1%
- 11am–2pm372 flights87.6%
- 2pm–5pm733 flights83.0%
- 5pm–8pm587 flights79.5%
- 8pm–5am514 flights74.1%
Scale runs 65% to 95%. Rows with fewer than 30 flights show a dash.
Book the morning departure. Flights leaving between 8am–11am arrive on time 89.1% of the time, against 74.1% for the overnight 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 8am–11am window is the busiest, with 737 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 12 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 78.0% on time, 12 points below September, the best at 90.1%. 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. January was the busiest month here, with 256 flights.
Across the week, Wednesday is the strongest day at 88.8% on time and Monday the weakest at 80.1%. 9 points is a smaller lever than departure hour, but it is free.
Delay causes
Why this route gets delayed
One category carries most of the weight here. Carrier accounts for 59% of the 30,000 delay minutes carriers reported, and the remaining four split what is left. The split is by minutes rather than by flights, so a few very long delays count for as much as many short ones.
- 59%Carrier
- 20%Late-arriving aircraft
- 15%National Airspace System
- 6%Extreme weather
The largest share of delay minutes, 59%, 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 18,000 of the 30,000 delay minutes reported here. The split is drawn from 29,841 reported delay minutes.
Cancellations are rare at 0.40%, below the national 1.81% and low enough to earn the plus on the grade. Roughly one flight in 100 is called off; the risk here is arriving late, not not arriving.
Connections and stage length
What a delay here actually costs
5.3% 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 are the about an hour kind, which a normal layover absorbs.
At 1,590 miles this is transcontinental flying, and long routes get a quiet structural advantage. Scheduled block time on a flight this length carries more padding in absolute minutes, so a twenty-minute late departure often still becomes an on-time arrival. Read the on-time rate here as slightly flattering next to a short-haul route with the same operational quality.
The return leg is a different operation and performs like one: it runs 87.3% on time across 2,972 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 2,965 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.
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 90.1% on time and July 78.0%, a swing of 12 points. If the dates move at all, move them out of July before you think about anything else. 2,947 completed flights over 12 months sit behind that.
Common questions
ATL to SLC questions
How often is ATL to SLC delayed?
About one flight in six arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 17.0% of the 2,965 flights in this analysis, against 22.4% nationally. Delayed flights are late by about an hour on average.
How reliable is ATL to SLC compared with the rest of the country?
83.0% of flights arrive on time here against a national 77.6%, a difference of 5 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 SLC?
The 8am–11am departure window is the strongest at 89.1% on time. The 8pm–5am window is the weakest at 74.1%, 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 SLC?
July is the weakest month at 78.0% on time, compared with 90.1% in September. Across the year that is 12 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
- SLC to ATL — the return legseparate record
- Hartsfield-Jackson Atlanta International (ATL) delay statistics
- Salt Lake City International (SLC) delay statistics
- Delta Air Lines on-time record83.0%
- Frontier Airlines on-time record66.7%
- The best time of day to fly, according to 7.04 million flight records
- Worst months to fly in the US, ranked by the data
Direction matters. ATL to SLC and SLC to ATL are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Updated monthly. How this data is collected.