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Flight Reliability

DL 1015 · Delta Air Lines

Washington → Seattle (IAD–SEA)96% of its flights flew this route. The rest (DTW–FLL) are included in these numbers.

77
Usually Fine
WanderNerd Reliability Score
77%
Arrive within 15 minutes
12 min
Average arrival delay
1.4%
Cancelled
8 min early
Median arrival delay

Based on 365 historical flights. Data through May 2026.

What the data says

Morning flights do better here.

DL 1015 departing between 6–9 AM arrived on time 79% of the time, versus 44% between 6–9 PM.

Thursdays have been rough.

DL 1015 arrived on time 88% of the time on Mondays and just 69% on Thursdays. That gap is worth planning around.

A bit behind the Delta Air Lines network.

DL 1015 arrived on time 77% of the time, versus 81% across the Delta Air Lines network.

Trending in the right direction.

DL 1015 arrived on time 77% of the time over the last three months in the data, compared with 63% in the three months before that.

The breakdown

On-time by weekday
  • Mon88%(50 flights)
  • Tue71%(52 flights)
  • Wed79%(52 flights)
  • Thu69%(52 flights)
  • Fri82%(51 flights)
  • Sat80%(50 flights)
  • Sun73%(52 flights)
On-time by departure window
  • 6–9 AM79%(343 flights)
  • 6–9 PM44%(16 flights)
On-time trend by month
94%
May

Jun 79% → May 94% on time

On-time arrival percentage by month
MonthOn-time percentageFlights
June 202579%29
July 202590%31
August 202587%31
September 202590%30
October 202587%31
November 202573%30
December 202552%31
January 202660%30
February 202678%27
March 202645%29
April 202693%29
May 202694%31
Departures on time
85%
Diverted
0.3%
Flights flown
359
Months covered
12

Same route, other flights

Keep nerding

Based on 365 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.