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Flight Reliability

DL 5821 · Delta Air Lines

This number covered several routes in this period.

One number, several routes.

Airlines reuse flight numbers, and DL 5821 moved between routes during this period. Numbers below combine all of them, so treat them as background, not a verdict. For a cleaner answer, check the route you are actually flying.

Combined across all its routes

84%
Arrive within 15 minutes
1 min early
Average arrival delay
4.5%
Cancelled
7 min early
Median arrival delay

Based on 445 historical flights. Data through May 2026.

The breakdown

On-time by weekday
  • Mon83%(54 flights)
  • Tue72%(60 flights)
  • Wed90%(62 flights)
  • Thu90%(61 flights)
  • Fri91%(63 flights)
  • Sat87%(60 flights)
  • Sun70%(57 flights)
On-time by departure window
  • 6–9 AM88%(184 flights)
  • 9 AM–12 PM85%(117 flights)
  • 12–3 PM75%(115 flights)
  • 3–6 PM—(1 flights)
On-time trend by month
87%
May

Jun 91% → May 87% on time

On-time arrival percentage by month
MonthOn-time percentageFlights
June 202591%23
July 202592%26
August 2025100%31
September 202583%29
October 202581%31
November 202586%28
December 202586%21
January 202682%51
February 202672%46
March 202677%56
April 202683%60
May 202687%15
Departures on time
88%
Diverted
1.8%
Flights flown
417
Months covered
12

Keep nerding

Based on 445 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.