Flight WN3978
Southwest Airlines flight WN3978
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Watch Ground Delay Program SAN
Ground Delay Program at San Diego International Airport (SAN): Average 37 minutes, up to 1 hour and 11 minutes
Reason: airport volume
Airport status
Raleigh/Durham (RDU) to Austin (AUS)
Historically, this flight arrives 15+ minutes late 17% of the time, and when it is late the delay averages 70 minutes. It was cancelled 0.0% of the time.
- On-time arrivals
- 83.3%
- Less than 15 minutes late
- Cancelled
- 0.0%
- Of scheduled flights
- Average delay when late
- 70 min
- Flights arriving 15+ minutes late
- Flights tracked
- 42
- Scheduled flights in the period
What caused the delays
- Airline (crew, maintenance, cleaning) 71%
- Air traffic control & airport 16%
- Late-arriving aircraft 14%
- Extreme weather 0%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
Orlando (MCO) to San Juan (SJU)
Historically, this flight arrives 15+ minutes late 16% of the time, and when it is late the delay averages 47 minutes. It was cancelled 0.0% of the time.
- On-time arrivals
- 83.9%
- Less than 15 minutes late
- Cancelled
- 0.0%
- Of scheduled flights
- Average delay when late
- 47 min
- Flights arriving 15+ minutes late
- Flights tracked
- 31
- Scheduled flights in the period
What caused the delays
- Airline (crew, maintenance, cleaning) 53%
- Late-arriving aircraft 41%
- Air traffic control & airport 6%
- Extreme weather 0%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
Portland (PDX) to Baltimore (BWI)
Historically, this flight arrives 15+ minutes late 19% of the time, and when it is late the delay averages 56 minutes. It was cancelled 0.0% of the time.
- On-time arrivals
- 80.6%
- Less than 15 minutes late
- Cancelled
- 0.0%
- Of scheduled flights
- Average delay when late
- 56 min
- Flights arriving 15+ minutes late
- Flights tracked
- 31
- Scheduled flights in the period
What caused the delays
- Late-arriving aircraft 77%
- Airline (crew, maintenance, cleaning) 16%
- Air traffic control & airport 7%
- Extreme weather 0%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
Chicago (MDW) to Philadelphia (PHL)
Historically, this flight arrives 15+ minutes late 23% of the time, and when it is late the delay averages 69 minutes. It was cancelled 3.6% of the time.
- On-time arrivals
- 76.9%
- Less than 15 minutes late
- Cancelled
- 3.6%
- Of scheduled flights
- Average delay when late
- 69 min
- Flights arriving 15+ minutes late
- Flights tracked
- 28
- Scheduled flights in the period
What caused the delays
- Late-arriving aircraft 58%
- Airline (crew, maintenance, cleaning) 26%
- Air traffic control & airport 16%
- Extreme weather 0%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
St Louis (STL) to San Antonio (SAT)
Historically, this flight arrives 15+ minutes late 26% of the time, and when it is late the delay averages 58 minutes. It was cancelled 0.0% of the time.
- On-time arrivals
- 74.1%
- Less than 15 minutes late
- Cancelled
- 0.0%
- Of scheduled flights
- Average delay when late
- 58 min
- Flights arriving 15+ minutes late
- Flights tracked
- 27
- Scheduled flights in the period
What caused the delays
- Late-arriving aircraft 68%
- Airline (crew, maintenance, cleaning) 17%
- Air traffic control & airport 12%
- Extreme weather 3%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
New Orleans (MSY) to Chicago (MDW)
Historically, this flight arrives 15+ minutes late 6% of the time, and when it is late the delay averages 40 minutes. It was cancelled 15.0% of the time.
- On-time arrivals
- 93.8%
- Less than 15 minutes late
- Cancelled
- 15.0%
- Of scheduled flights
- Average delay when late
- 40 min
- Flights arriving 15+ minutes late
- Flights tracked
- 20
- Scheduled flights in the period
What caused the delays
- Air traffic control & airport 100%
- Airline (crew, maintenance, cleaning) 0%
- Late-arriving aircraft 0%
- Extreme weather 0%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
Ontario (ONT) to Denver (DEN)
Only 17 flights on record, which is too few for reliable odds.
- On-time arrivals
- 64.7%
- Less than 15 minutes late
- Cancelled
- 0.0%
- Of scheduled flights
- Average delay when late
- 37 min
- Flights arriving 15+ minutes late
- Flights tracked
- 17
- Scheduled flights in the period
What caused the delays
- Late-arriving aircraft 65%
- Air traffic control & airport 24%
- Airline (crew, maintenance, cleaning) 11%
- Extreme weather 0%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
Valparaiso (VPS) to Baltimore (BWI)
Only 12 flights on record, which is too few for reliable odds.
- On-time arrivals
- 40.0%
- Less than 15 minutes late
- Cancelled
- 0.0%
- Of scheduled flights
- Average delay when late
- 61 min
- Flights arriving 15+ minutes late
- Flights tracked
- 12
- Scheduled flights in the period
What caused the delays
- Air traffic control & airport 71%
- Late-arriving aircraft 28%
- Airline (crew, maintenance, cleaning) 1%
- Extreme weather 0%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
Philadelphia (PHL) to Tampa (TPA)
Only 8 flights on record, which is too few for reliable odds.
- On-time arrivals
- 62.5%
- Less than 15 minutes late
- Cancelled
- 0.0%
- Of scheduled flights
- Average delay when late
- 54 min
- Flights arriving 15+ minutes late
- Flights tracked
- 8
- Scheduled flights in the period
What caused the delays
- Late-arriving aircraft 74%
- Airline (crew, maintenance, cleaning) 23%
- Air traffic control & airport 3%
- Extreme weather 0%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
San Diego (SAN) to Sacramento (SMF)
Only 8 flights on record, which is too few for reliable odds.
- On-time arrivals
- 62.5%
- Less than 15 minutes late
- Cancelled
- 0.0%
- Of scheduled flights
- Average delay when late
- 49 min
- Flights arriving 15+ minutes late
- Flights tracked
- 8
- Scheduled flights in the period
What caused the delays
- Late-arriving aircraft 71%
- Airline (crew, maintenance, cleaning) 16%
- Air traffic control & airport 12%
- Extreme weather 0%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
Chicago (MDW) to St Louis (STL)
Only 5 flights on record, which is too few for reliable odds.
- On-time arrivals
- 100.0%
- Less than 15 minutes late
- Cancelled
- 0.0%
- Of scheduled flights
- Average delay when late
- —
- Flights arriving 15+ minutes late
- Flights tracked
- 5
- Scheduled flights in the period
Philadelphia (PHL) to Orlando (MCO)
Only 5 flights on record, which is too few for reliable odds.
- On-time arrivals
- 80.0%
- Less than 15 minutes late
- Cancelled
- 0.0%
- Of scheduled flights
- Average delay when late
- 32 min
- Flights arriving 15+ minutes late
- Flights tracked
- 5
- Scheduled flights in the period
What caused the delays
- Airline (crew, maintenance, cleaning) 68%
- Late-arriving aircraft 18%
- Air traffic control & airport 14%
- Extreme weather 0%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
Show as table
| Month | On time | Flights |
|---|---|---|
| September 2025 | 80.0% | 30 |
| October 2025 | 83.9% | 31 |
| November 2025 | 61.5% | 13 |
| December 2025 | 75.0% | 4 |
| January 2026 | 100.0% | 1 |
| February 2026 | 57.1% | 7 |
| March 2026 | 82.0% | 55 |
| April 2026 | 86.2% | 30 |
| May 2026 | 76.2% | 21 |
| June 2026 | 66.7% | 15 |
| July 2026 | 85.7% | 14 |
| August 2026 | 45.5% | 13 |
Source: U.S. DOT Bureau of Transportation Statistics on-time data, September 2025 – August 2026. Covers flights operated by reporting U.S. carriers. About our data