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Flight Reliability

DL 2666 · Delta Air Lines

Salt Lake City → St. Louis (SLC–STL)

86
Pretty Reliable
WanderNerd Reliability Score
79%
Arrive within 15 minutes
6 min
Average arrival delay
0.3%
Cancelled
8 min early
Median arrival delay

Based on 355 historical flights. Data through May 2026.

What the data says

The late departure is the smart one here.

DL 2666 departing between 9 PM–12 AM arrived on time 100% of the time, versus 76% between 6–9 PM.

Sunday scaries are real for this one.

DL 2666 arrived on time 87% of the time on Wednesdays and just 66% on Sundays. That gap is worth planning around.

A bit behind the SLC–STL route.

DL 2666 arrived on time 79% of the time, versus 85% across the SLC–STL route.

It basically never cancels.

Out of 355 scheduled flights, only 0.3% were cancelled.

The breakdown

On-time by weekday
  • Mon85%(52 flights)
  • Tue81%(52 flights)
  • Wed87%(52 flights)
  • Thu77%(52 flights)
  • Fri78%(51 flights)
  • Sat79%(42 flights)
  • Sun66%(53 flights)
On-time by departure window
  • 9 AM–12 PM—(1 flights)
  • 3–6 PM84%(86 flights)
  • 6–9 PM76%(257 flights)
  • 9 PM–12 AM100%(10 flights)
On-time trend by month
77%
May

Jun 77% → May 77% on time

On-time arrival percentage by month
MonthOn-time percentageFlights
June 202577%30
July 202571%31
August 202574%31
September 202573%30
October 202570%27
November 202581%26
December 202571%28
January 202690%31
February 202689%28
March 202690%31
April 202680%30
May 202677%31
Departures on time
75%
Diverted
0%
Flights flown
354
Months covered
12

Same route, other flights

Keep nerding

Based on 355 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.