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Flight Reliability

DL 2021 · Delta Air Lines

Miami → Salt Lake City (MIA–SLC)

80
Pretty Reliable
WanderNerd Reliability Score
74%
Arrive within 15 minutes
11 min
Average arrival delay
0.5%
Cancelled
0 min
Median arrival delay

Based on 364 historical flights. Data through May 2026.

What the data says

Morning flights do better here.

DL 2021 departing between 6–9 AM arrived on time 85% of the time, versus 65% between 6–9 PM.

Sunday scaries are real for this one.

DL 2021 arrived on time 86% of the time on Tuesdays and just 68% on Sundays. That gap is worth planning around.

Lagging the Delta Air Lines network.

DL 2021 arrived on time 74% of the time, versus 81% across the Delta Air Lines network.

Trending in the right direction.

DL 2021 arrived on time 87% of the time over the last three months in the data, compared with 76% in the three months before that.

The breakdown

On-time by weekday
  • Mon69%(51 flights)
  • Tue86%(51 flights)
  • Wed81%(52 flights)
  • Thu69%(52 flights)
  • Fri73%(51 flights)
  • Sat75%(52 flights)
  • Sun68%(53 flights)
On-time by departure window
  • 6–9 AM85%(161 flights)
  • 3–6 PM78%(23 flights)
  • 6–9 PM65%(178 flights)
On-time trend by month
87%
May

Jun 60% → May 87% on time

On-time arrival percentage by month
MonthOn-time percentageFlights
June 202560%30
July 202552%31
August 202571%31
September 202580%30
October 202580%30
November 202563%30
December 202561%31
January 202681%31
February 202686%28
March 202693%29
April 202680%30
May 202687%31
Departures on time
74%
Diverted
0%
Flights flown
362
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.