Route profile
BWI→GSP
Flight reliability, delays and best times to fly from Baltimore to Greenville/Greer/Spartanburg. · 426 miles
Right now
Current conditions at both ends of this route.
Aviation weather is not currently a factor.
FlyerIntel does not currently have live operational data for this airport.
Airport conditions describe the airfield, not any individual flight. An airport operating normally is not a guarantee that a specific flight will depart on time.
Route reliability
July 2023 – June 2026
Better than 53% of comparable major US routes (4,577 compared)
Calculated from 1,832 flights. How this is calculated
Source: US DOT Bureau of Transportation Statistics · Data covering July 2023 – June 2026
Best time to fly
On-time arrival rate by scheduled local departure time.
BWI → GSP flights departing 5–9 AM arrived on time 91.5% of the time, against 68.2% for 6–9 PM departures — a gap of 23.3 percentage points.
By departure window
By departure hour
Source: FlyerIntel analysis of US DOT BTS data · July 2023 – June 2026 · Buckets with fewer than 120 flights are not scored.
Why BWI → GSP runs late
Where US DOT attributed the delay minutes on this route.
the inbound aircraft was late, so this flight started late
crew, maintenance, boarding, fuelling — within the carrier’s control
airspace and airport capacity, including weather-driven flow control
weather severe enough to stop this flight specifically
screening or terminal security incidents
Share of the delay minutes US DOT attributed to each cause for BWI → GSP. A single late flight can carry more than one cause, and only delays of fifteen minutes or more are attributed at all.
A route inherits the problems of both ends and of the aircraft flying it. A large share attributed to late-arriving aircraft usually means the departure sits late in a busy rotation rather than that anything about this city pair is difficult, which is why the same route often performs very differently at different times of day.
Airlines on this route
Performance by the carrier that actually operated the flight.
| Carrier | Flights | On time | Cancelled | Median delay | Severe |
|---|---|---|---|---|---|
| Southwest Airlines | 1,832 | 78.2% | 0.93% | -4 min | 7.0% |
Source: FlyerIntel analysis of US DOT BTS data · July 2023 – June 2026 · Carriers with fewer than 200 flights on this route are not listed.
Weekly and seasonal patterns
By day of week
Tuesday is historically the most reliable day and Monday the least, a gap of 8.4 percentage points.
By month
July is historically the weakest month and November the strongest, a spread of 23.5 percentage points.
Historical trend
On-time arrival rate by month.
Over the most recent 12 months (2025-07 to 2026-06), on-time arrivals averaged 82.2% against 75.4% in the 12 months before — improving by 6.8 percentage points.
Source: FlyerIntel analysis of US DOT BTS data · July 2023 – June 2026
Data and methodology
All figures on this page are calculated by FlyerIntel from 1,832 BWI → GSP flight records published by the US DOT Bureau of Transportation Statistics, covering July 2023 – June 2026. A flight is counted as delayed when it arrives 15 or more minutes after its scheduled arrival time, following BTS methodology. Cancelled and diverted flights have no arrival time and are excluded from on-time rates rather than counted as late.
Full methodology · Data sources · Report a problem
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