Flight Reliability
DL 1731 · Delta Air Lines
Denver → Seattle (DEN–SEA)
94
Nerd Approved
WanderNerd Reliability Score
- 89%
- Arrive within 15 minutes
- 1 min
- Average arrival delay
- 0.8%
- Cancelled
- 11 min early
- Median arrival delay
Based on 364 historical flights. Data through May 2026.
What the data says
Sunday scaries are real for this one.
DL 1731 arrived on time 98% of the time on Tuesdays and just 79% on Sundays. That gap is worth planning around.
Well ahead of the DEN–SEA route.
DL 1731 arrived on time 89% of the time, versus 74% across the DEN–SEA route.
Better than the Delta Air Lines network average.
DL 1731 arrived on time 89% of the time, versus 81% across the Delta Air Lines network.
Trending in the right direction.
DL 1731 arrived on time 96% of the time over the last three months in the data, compared with 83% in the three months before that.
The breakdown
- Mon86%(51 flights)
- Tue98%(51 flights)
- Wed89%(52 flights)
- Thu85%(52 flights)
- Fri96%(52 flights)
- Sat92%(50 flights)
- Sun79%(53 flights)
97%
May
Jun 83% → May 97% on time
| Month | On-time percentage | Flights |
|---|---|---|
| June 2025 | 83% | 30 |
| July 2025 | 87% | 31 |
| August 2025 | 94% | 31 |
| September 2025 | 100% | 30 |
| October 2025 | 87% | 30 |
| November 2025 | 83% | 30 |
| December 2025 | 62% | 29 |
| January 2026 | 94% | 31 |
| February 2026 | 93% | 28 |
| March 2026 | 90% | 30 |
| April 2026 | 100% | 30 |
| May 2026 | 97% | 31 |
- Departures on time
- 93%
- Diverted
- 0%
- Flights flown
- 361
- 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.