Flight WN4539
Southwest Airlines flight WN4539
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Alerts at this flight's airports
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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
-
Advisory Airport Closure SNA
Airport Closure at John Wayne Orange County International Airport (SNA): Reopens Nov 08 at 14:15 UTC.
Airport status
Boise (BOI) to Oakland (OAK)
Historically, this flight arrives 15+ minutes late 43% of the time, and when it is late the delay averages 46 minutes. It was cancelled 0.0% of the time.
- On-time arrivals
- 56.7%
- Less than 15 minutes late
- Cancelled
- 0.0%
- Of scheduled flights
- Average delay when late
- 46 min
- Flights arriving 15+ minutes late
- Flights tracked
- 60
- Scheduled flights in the period
What caused the delays
- Late-arriving aircraft 77%
- Airline (crew, maintenance, cleaning) 21%
- Air traffic control & airport 3%
- Extreme weather 0%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
San Diego (SAN) to San Jose (SJC)
Historically, this flight arrives 15+ minutes late 26% of the time, and when it is late the delay averages 69 minutes. It was cancelled 1.7% of the time.
- On-time arrivals
- 74.1%
- Less than 15 minutes late
- Cancelled
- 1.7%
- Of scheduled flights
- Average delay when late
- 69 min
- Flights arriving 15+ minutes late
- Flights tracked
- 59
- Scheduled flights in the period
What caused the delays
- Late-arriving aircraft 83%
- Airline (crew, maintenance, cleaning) 17%
- Air traffic control & airport 0%
- Extreme weather 0%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
Santa Ana (SNA) to Sacramento (SMF)
Historically, this flight arrives 15+ minutes late 6% of the time, and when it is late the delay averages 77 minutes. It was cancelled 0.0% of the time.
- On-time arrivals
- 93.5%
- Less than 15 minutes late
- Cancelled
- 0.0%
- Of scheduled flights
- Average delay when late
- 77 min
- Flights arriving 15+ minutes late
- Flights tracked
- 31
- Scheduled flights in the period
What caused the delays
- Airline (crew, maintenance, cleaning) 93%
- Air traffic control & airport 7%
- Late-arriving aircraft 0%
- Extreme weather 0%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
Orlando (MCO) to Indianapolis (IND)
Historically, this flight arrives 15+ minutes late 59% of the time, and when it is late the delay averages 75 minutes. It was cancelled 3.3% of the time.
- On-time arrivals
- 41.4%
- Less than 15 minutes late
- Cancelled
- 3.3%
- Of scheduled flights
- Average delay when late
- 75 min
- Flights arriving 15+ minutes late
- Flights tracked
- 30
- Scheduled flights in the period
What caused the delays
- Late-arriving aircraft 44%
- Airline (crew, maintenance, cleaning) 35%
- Extreme weather 14%
- Air traffic control & airport 7%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
Houston (HOU) to Memphis (MEM)
Historically, this flight arrives 15+ minutes late 57% of the time, and when it is late the delay averages 46 minutes. It was cancelled 0.0% of the time.
- On-time arrivals
- 42.9%
- Less than 15 minutes late
- Cancelled
- 0.0%
- Of scheduled flights
- Average delay when late
- 46 min
- Flights arriving 15+ minutes late
- Flights tracked
- 28
- Scheduled flights in the period
What caused the delays
- Late-arriving aircraft 82%
- Airline (crew, maintenance, cleaning) 13%
- Air traffic control & airport 5%
- Extreme weather 0%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
Las Vegas (LAS) to St Louis (STL)
Historically, this flight arrives 15+ minutes late 63% of the time, and when it is late the delay averages 59 minutes. It was cancelled 0.0% of the time.
- On-time arrivals
- 37.0%
- Less than 15 minutes late
- Cancelled
- 0.0%
- Of scheduled flights
- Average delay when late
- 59 min
- Flights arriving 15+ minutes late
- Flights tracked
- 27
- Scheduled flights in the period
What caused the delays
- Late-arriving aircraft 70%
- Airline (crew, maintenance, cleaning) 29%
- Air traffic control & airport 1%
- Extreme weather 0%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
Chicago (MDW) to Charleston (CHS)
Historically, this flight arrives 15+ minutes late 19% of the time, and when it is late the delay averages 30 minutes. It was cancelled 0.0% of the time.
- On-time arrivals
- 81.5%
- Less than 15 minutes late
- Cancelled
- 0.0%
- Of scheduled flights
- Average delay when late
- 30 min
- Flights arriving 15+ minutes late
- Flights tracked
- 27
- Scheduled flights in the period
What caused the delays
- Late-arriving aircraft 65%
- Airline (crew, maintenance, cleaning) 20%
- Air traffic control & airport 15%
- Extreme weather 0%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
Oakland (OAK) to Las Vegas (LAS)
Historically, this flight arrives 15+ minutes late 59% of the time, and when it is late the delay averages 51 minutes. It was cancelled 0.0% of the time.
- On-time arrivals
- 40.7%
- Less than 15 minutes late
- Cancelled
- 0.0%
- Of scheduled flights
- Average delay when late
- 51 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) 30%
- Air traffic control & airport 2%
- Extreme weather 0%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
Houston (HOU) to Chicago (MDW)
Only 13 flights on record, which is too few for reliable odds.
- On-time arrivals
- 66.7%
- Less than 15 minutes late
- Cancelled
- 7.7%
- Of scheduled flights
- Average delay when late
- 34 min
- Flights arriving 15+ minutes late
- Flights tracked
- 13
- Scheduled flights in the period
What caused the delays
- Late-arriving aircraft 79%
- Airline (crew, maintenance, cleaning) 17%
- Air traffic control & airport 5%
- Extreme weather 0%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
Sacramento (SMF) to Seattle (SEA)
Only 13 flights on record, which is too few for reliable odds.
- On-time arrivals
- 69.2%
- Less than 15 minutes late
- Cancelled
- 0.0%
- Of scheduled flights
- Average delay when late
- 54 min
- Flights arriving 15+ minutes late
- Flights tracked
- 13
- Scheduled flights in the period
What caused the delays
- Late-arriving aircraft 64%
- Air traffic control & airport 28%
- Airline (crew, maintenance, cleaning) 8%
- 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
- 87.5%
- Less than 15 minutes late
- Cancelled
- 0.0%
- Of scheduled flights
- Average delay when late
- 110 min
- Flights arriving 15+ minutes late
- Flights tracked
- 8
- Scheduled flights in the period
What caused the delays
- Late-arriving aircraft 96%
- Air traffic control & airport 4%
- Airline (crew, maintenance, cleaning) 0%
- Extreme weather 0%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
Denver (DEN) to Oklahoma City (OKC)
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
San Jose (SJC) to Seattle (SEA)
Only 5 flights on record, which is too few for reliable odds.
- On-time arrivals
- 60.0%
- Less than 15 minutes late
- Cancelled
- 0.0%
- Of scheduled flights
- Average delay when late
- 70 min
- Flights arriving 15+ minutes late
- Flights tracked
- 5
- Scheduled flights in the period
What caused the delays
- Late-arriving aircraft 76%
- Airline (crew, maintenance, cleaning) 24%
- Air traffic control & airport 0%
- Extreme weather 0%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
Sacramento (SMF) to Denver (DEN)
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
Albuquerque (ABQ) to Dallas (DAL)
Only 4 flights on record, which is too few for reliable odds.
- On-time arrivals
- 75.0%
- Less than 15 minutes late
- Cancelled
- 0.0%
- Of scheduled flights
- Average delay when late
- 21 min
- Flights arriving 15+ minutes late
- Flights tracked
- 4
- 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).
Dallas (DAL) to Valparaiso (VPS)
Only 4 flights on record, which is too few for reliable odds.
- On-time arrivals
- 50.0%
- Less than 15 minutes late
- Cancelled
- 0.0%
- Of scheduled flights
- Average delay when late
- 35 min
- Flights arriving 15+ minutes late
- Flights tracked
- 4
- Scheduled flights in the period
What caused the delays
- Airline (crew, maintenance, cleaning) 64%
- Late-arriving aircraft 36%
- Air traffic control & airport 0%
- Extreme weather 0%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
San Jose (SJC) to Denver (DEN)
Only 4 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
- 4
- Scheduled flights in the period
Spokane (GEG) to San Jose (SJC)
Only 1 flight 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
- 1
- Scheduled flights in the period
Show as table
| Month | On time | Flights |
|---|---|---|
| September 2025 | 76.3% | 39 |
| October 2025 | 88.5% | 52 |
| November 2025 | 87.1% | 31 |
| December 2025 | 70.0% | 31 |
| January 2026 | 50.0% | 15 |
| February 2026 | 31.6% | 19 |
| March 2026 | 48.0% | 25 |
| April 2026 | 20.0% | 5 |
| June 2026 | 41.2% | 51 |
| July 2026 | 55.2% | 58 |
| August 2026 | 72.0% | 25 |
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