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Flight Reliability

DL 423 · Delta Air Lines

Atlanta → Salt Lake City (ATL–SLC)

91
Nerd Approved
WanderNerd Reliability Score
86%
Arrive within 15 minutes
1 min
Average arrival delay
0.3%
Cancelled
6 min early
Median arrival delay

Based on 365 historical flights. Data through May 2026.

What the data says

Thursdays have been rough.

DL 423 arrived on time 94% of the time on Fridays and just 79% on Thursdays. That gap is worth planning around.

A bit ahead of the ATL–SLC route.

DL 423 arrived on time 86% of the time, versus 83% across the ATL–SLC route.

A bit ahead of the Delta Air Lines network.

DL 423 arrived on time 86% of the time, versus 81% across the Delta Air Lines network.

It basically never cancels.

Out of 365 scheduled flights, only 0.3% were cancelled.

The breakdown

On-time by weekday
  • Mon86%(51 flights)
  • Tue85%(52 flights)
  • Wed89%(52 flights)
  • Thu79%(52 flights)
  • Fri94%(51 flights)
  • Sat89%(52 flights)
  • Sun79%(53 flights)
On-time trend by month
87%
May

Jun 87% → May 87% on time

On-time arrival percentage by month
MonthOn-time percentageFlights
June 202587%30
July 202581%31
August 202581%31
September 202597%30
October 202584%31
November 2025100%30
December 202577%31
January 202687%31
February 202693%28
March 202670%30
April 202687%30
May 202687%30
Departures on time
89%
Diverted
0.3%
Flights flown
363
Months covered
12

Same route, other flights

Keep nerding

Based on 365 historical flights, because apparently we checked. Historical flight data: U.S. Bureau of Transportation Statistics, June 2025 – May 2026. Data through May 2026. How we calculate this.