Flight Reliability
DL 1091 · Delta Air Lines
Salt Lake City → San Francisco (SLC–SFO)
81
Pretty Reliable
WanderNerd Reliability Score
- 75%
- Arrive within 15 minutes
- 6 min
- Average arrival delay
- 0.3%
- Cancelled
- 1 min early
- Median arrival delay
Based on 335 historical flights. Data through May 2026.
What the data says
Sunday scaries are real for this one.
DL 1091 arrived on time 83% of the time on Tuesdays and just 62% on Sundays. That gap is worth planning around.
A bit behind the Delta Air Lines network.
DL 1091 arrived on time 75% of the time, versus 81% across the Delta Air Lines network.
It basically never cancels.
Out of 335 scheduled flights, only 0.3% were cancelled.
Slipping a little lately.
DL 1091 arrived on time 69% of the time over the last three months in the data, compared with 73% in the three months before that.
The breakdown
- Mon65%(51 flights)
- Tue83%(46 flights)
- Wed78%(46 flights)
- Thu76%(49 flights)
- Fri82%(49 flights)
- Sat81%(41 flights)
- Sun62%(52 flights)
55%
May
Jun 83% → May 55% on time
| Month | On-time percentage | Flights |
|---|---|---|
| June 2025 | 83% | 30 |
| July 2025 | 81% | 31 |
| August 2025 | 65% | 31 |
| September 2025 | 80% | 30 |
| October 2025 | 79% | 24 |
| November 2025 | 84% | 19 |
| December 2025 | 83% | 29 |
| January 2026 | 60% | 25 |
| February 2026 | 75% | 24 |
| March 2026 | 90% | 30 |
| April 2026 | 63% | 30 |
| May 2026 | 55% | 31 |
- Departures on time
- 81%
- Diverted
- 0%
- Flights flown
- 334
- Months covered
- 12
Same route, other flights
Keep nerding
Based on 335 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.