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Flight Reliability

DL 2921 · Delta Air Lines

Salt Lake City → Seattle (SLC–SEA)

91
Nerd Approved
WanderNerd Reliability Score
86%
Arrive within 15 minutes
0 min
Average arrival delay
0.7%
Cancelled
9 min early
Median arrival delay

Based on 287 historical flights. Data through May 2026.

What the data says

Friday is doing you no favors.

DL 2921 arrived on time 93% of the time on Tuesdays and just 77% on Fridays. That gap is worth planning around.

A bit ahead of the SLC–SEA route.

DL 2921 arrived on time 86% of the time, versus 80% across the SLC–SEA route.

A bit ahead of the Delta Air Lines network.

DL 2921 arrived on time 86% of the time, versus 81% across the Delta Air Lines network.

Trending in the right direction.

DL 2921 arrived on time 92% of the time over the last three months in the data, compared with 74% in the three months before that.

The breakdown

On-time by weekday
  • Mon78%(40 flights)
  • Tue93%(41 flights)
  • Wed85%(41 flights)
  • Thu93%(41 flights)
  • Fri77%(39 flights)
  • Sat93%(41 flights)
  • Sun83%(42 flights)
On-time by departure window
  • 9 AM–12 PM—(4 flights)
  • 12–3 PM86%(277 flights)
  • 3–6 PM—(4 flights)
On-time trend by month
87%
May

Jun 93% → May 87% on time

On-time arrival percentage by month
MonthOn-time percentageFlights
June 202593%30
July 202587%31
August 202579%29
September 202593%30
October 202577%30
November 202582%28
December 202563%19
March 202691%23
April 202697%30
May 202687%31
Departures on time
86%
Diverted
0%
Flights flown
285
Months covered
12

Same route, other flights

Keep nerding

Based on 287 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.