May 2026 · US Department of Transportation filings
San Diego to Sacramento on Southwest Airlines
Southwest Airlines flew 676 flights between San Diego (SAN) and Sacramento (SMF) in May 2026. On the worse direction, 33.1% arrived more than 15 minutes late. These are the airline's own filings to the federal government, not our estimates, and every figure below shows the number of flights behind it.
Both directions, measured separately
San Diego (SAN) to Sacramento (SMF)
- Arrived over 15 min late
- 27.8%of 338 flights
- Cancelled
- 0%
- Average delay
- 13.7min
Of every minute of delay recorded on Southwest Airlines flights San Diego (SAN) to Sacramento (SMF), 92.4% traces back to the airline and 0% to weather. That matters when a delay is explained to you at the gate, and it matters for what you can ask for: the commitments US airlines make to rebook you and cover meals apply to delays within their control, not to weather.
- The airline — 23%
Crew, maintenance, fuelling, baggage — the carrier's own operation. - Late inbound aircraft — 69.4%
The plane arrived late from its previous flight, which is knock-on from the same airline. - Air traffic system — 3.8%
Volume, routing and airport capacity, attributed to the national airspace system.
“Traces back to the airline” is carrier delay plus late-inbound-aircraft delay added together. BTS reports those as two separate causes; combining them is our reading, on the grounds that a late inbound aircraft is the same airline's earlier delay arriving with the plane. The components are listed above so you can disagree.
Sacramento (SMF) to San Diego (SAN)
- Arrived over 15 min late
- 33.1%of 338 flights
- Cancelled
- 0.3%
- Average delay
- 15.7min
Of every minute of delay recorded on Southwest Airlines flights Sacramento (SMF) to San Diego (SAN), 71.4% traces back to the airline and 0% to weather. That matters when a delay is explained to you at the gate, and it matters for what you can ask for: the commitments US airlines make to rebook you and cover meals apply to delays within their control, not to weather.
- The airline — 17.8%
Crew, maintenance, fuelling, baggage — the carrier's own operation. - Late inbound aircraft — 53.6%
The plane arrived late from its previous flight, which is knock-on from the same airline. - Air traffic system — 26.6%
Volume, routing and airport capacity, attributed to the national airspace system.
“Traces back to the airline” is carrier delay plus late-inbound-aircraft delay added together. BTS reports those as two separate causes; combining them is our reading, on the grounds that a late inbound aircraft is the same airline's earlier delay arriving with the plane. The components are listed above so you can disagree.
Figures cover May 2026, a single reporting month, from the US DOT Bureau of Transportation Statistics On-Time Performance database. Retrieved 2026-07-28. Reporting under 14 CFR part 234 covers domestic US scheduled service only, so no international route appears — including anything to or from Mexico.
What you are owed when it does run late
Both airports are in the United States or a US territory, so this is a domestic itinerary and the significant-delay threshold is 3 hours. A 3 hours delay meets it.
- Full refund of the fare, taxes and ancillary fees — Owed under § 260.6(a) — but only if you decline what the airline offers instead. Accepting a rebooking, voucher or travel credit ends the refund right. If you want your money back, say no to the alternative.
- Paid back to your original form of payment — § 260.2 defines a prompt refund as 7 business days for a card purchase and 20 calendar days for anything else. Where you have refused a voucher, the airline cannot substitute one for cash.
- No cash compensation on top of the refund — Unlike EU 261, US law requires no compensation for the disruption itself. Meals and hotels come from the carrier's own customer service plan under 14 CFR 259.5, so they differ by airline — worth asking for, but not a statutory right.
How to read these numbers
“Late” means arriving more than 15 minutes after the scheduled gate time, which is the threshold the Department of Transportation uses. Cause shares describe delay minutes, not flights, so a small number of very long delays can dominate them. We publish a route only when it carries at least 300 flights in the window, because below that a couple of bad days produces a dramatic percentage that means nothing.
Reporting under 14 CFR part 234 covers domestic US service by the larger US carriers, so these pages cover neither international routes nor Mexican airlines.