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Flight Reliability

DL 1581 · Delta Air Lines

Denver → Salt Lake City (DEN–SLC)

98
Nerd Approved
WanderNerd Reliability Score
90%
Arrive within 15 minutes
5 min
Average arrival delay
0%
Cancelled
14 min early
Median arrival delay

Based on 364 historical flights. Data through May 2026.

What the data says

Friday is doing you no favors.

DL 1581 arrived on time 96% of the time on Thursdays. On Fridays: 87%.

Better than the DEN–SLC route average.

DL 1581 arrived on time 90% of the time, versus 78% across the DEN–SLC route.

Better than the Delta Air Lines network average.

DL 1581 arrived on time 90% of the time, versus 81% across the Delta Air Lines network.

It basically never cancels.

Out of 364 scheduled flights, only 0.0% were cancelled.

The breakdown

On-time by weekday
  • Mon88%(51 flights)
  • Tue90%(52 flights)
  • Wed87%(52 flights)
  • Thu96%(52 flights)
  • Fri87%(52 flights)
  • Sat90%(52 flights)
  • Sun91%(53 flights)
On-time trend by month
94%
May

Jun 90% → May 94% on time

On-time arrival percentage by month
MonthOn-time percentageFlights
June 202590%30
July 202574%31
August 2025100%31
September 202597%30
October 202594%31
November 202590%30
December 202577%31
January 202694%31
February 202696%28
March 202681%31
April 202693%29
May 202694%31
Departures on time
90%
Diverted
0%
Flights flown
364
Months covered
12

Same route, other flights

Keep nerding

Based on 364 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.