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Flight Reliability

DL 2851 · Delta Air Lines

Seattle → Denver (SEA–DEN)

81
Pretty Reliable
WanderNerd Reliability Score
78%
Arrive within 15 minutes
1 min
Average arrival delay
1.2%
Cancelled
10 min early
Median arrival delay

Based on 170 historical flights. Data through May 2026.

What the data says

Mondays have been rough.

DL 2851 arrived on time 84% of the time on Saturdays and just 67% on Mondays. That gap is worth planning around.

A bit behind the Delta Air Lines network.

DL 2851 arrived on time 78% of the time, versus 81% across the Delta Air Lines network.

Recent months have been rougher.

DL 2851 arrived on time 74% of the time over the last three months in the data, compared with 85% in the three months before that.

The breakdown

On-time by weekday
  • Mon67%(24 flights)
  • Tue83%(24 flights)
  • Wed71%(24 flights)
  • Thu79%(24 flights)
  • Fri83%(23 flights)
  • Sat84%(25 flights)
  • Sun79%(24 flights)
On-time trend by month
87%
May

Dec 82% → May 87% on time

On-time arrival percentage by month
MonthOn-time percentageFlights
December 202582%11
January 202687%31
February 202686%28
March 202667%30
April 202667%30
May 202687%31
Departures on time
79%
Diverted
0%
Flights flown
168
Months covered
7

Same route, other flights

Keep nerding

Based on 170 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.