Route on-time record
BWI to GSP: most on-time flights and the best time to fly
Baltimore (Baltimore/Washington International Thurgood Marshall Airport) to Greenville/Greer/Spartanburg (Greenville-Spartanburg International Airport). 720 nonstop flights in Jun 2025 to May 2026, 82% arrived within 15 minutes and 1.3% were cancelled. The most reliable flight number was Southwest 1958 at 8:30 AM.
Flying on a specific date? We’ll adjust for the month, the weekday and the forecast.
BWI → GSP
Baltimore to Greenville/Greer/Spartanburg: 720 nonstop flights a year
On time (12 months)
82%
Cancelled
1.3%
avg delay 15 min
Best time to leave
9 AM to noon
93% on time vs 72% 6 to 9 PM
Most reliable airline
Southwest
81% chance on time
Fares open on our travel partner (Aviasales). Pick the flight number you chose here.
Most reliable nonstop flights
Ranked by the chance the flight operates and arrives within 15 minutes of schedule, from Jun 2025 to May 2026 records.
#1 · Southwest 1958
8:30 AM → 10:10 AM1h 40m nonstop
Local times, typical schedule. Last flown 2026-05-30.
90%
chance on time
- On time (history)
- 100%
- Cancelled
- 0.0%
- Avg arrival delay
- 0 min
- Arrived on time 100% of the time (8 flights, Jun 2025 to May 2026).
- Departs outside BWI's trouble window (2 PM to 8 PM, when 81% of its 43 ground stops and delay programs started).
- Short track record (8 flights), so its score leans on the airline's record at this hour.
Limited track record · 8 flights
Find Southwest 1958 fares Opens this date on Aviasales#2 · Southwest 1350
11:40 AM → 1:10 PM1h 30m nonstop
Local times, typical schedule. Last flown 2026-05-31. Same departure also flew as Southwest 1517; its record covers all of them.
90%
chance on time
- On time (history)
- 93%
- Cancelled
- 0.0%
- Avg arrival delay
- 6 min
- Arrived on time 93% of the time (80 flights, Jun 2025 to May 2026).
- Never cancelled in 80 scheduled flights.
- Leaves in this route's most on-time window (9 AM to noon: 93% on time; 6 to 9 PM: 72%).
- Departs outside BWI's trouble window (2 PM to 8 PM, when 81% of its 43 ground stops and delay programs started).
Moderate track record · 80 flights
Find Southwest 1350 fares Opens this date on Aviasales#3 · Southwest 1143
7:20 PM → 8:55 PM1h 35m nonstop
Local times, typical schedule. Last flown 2026-05-31.
74%
chance on time
- On time (history)
- 74%
- Cancelled
- 0.0%
- Avg arrival delay
- 21 min
- Arrived on time 74% of the time (54 flights, Jun 2025 to May 2026).
- Never cancelled in 54 scheduled flights.
- Leaves in this route's least on-time window (6 to 9 PM: 72% on time; 9 AM to noon: 93%).
- Departs inside BWI's trouble window: 81% of its 43 ground stops and delay programs started between 2 PM and 8 PM.
Limited track record · 54 flights
Find Southwest 1143 fares Opens this date on Aviasales#4 · Southwest 1327
8:15 PM → 9:50 PM1h 35m nonstop
Local times, typical schedule. Last flown 2026-04-06.
72%
chance on time
- On time (history)
- 73%
- Cancelled
- 0.0%
- Avg arrival delay
- 32 min
- Arrived on time 73% of the time (33 flights, Jun 2025 to May 2026).
- Never cancelled in 33 scheduled flights.
- Leaves in this route's least on-time window (6 to 9 PM: 72% on time; 9 AM to noon: 93%).
- Departs outside BWI's trouble window (2 PM to 8 PM, when 81% of its 43 ground stops and delay programs started).
Limited track record · 33 flights
Find Southwest 1327 fares Opens this date on Aviasales
Airlines on this route
Season-adjusted chance of operating and arriving on time.
- Southwest Airlines81%
720 flights · 82% on time as flown · 1.3% cancel
On time by departure time
All airlines, scheduled local departure, Jun 2025 to May 2026.
- Before 9 AM92%
274 flights · avg delay 4 min
- 9 AM to noon93%
91 flights · avg delay 6 min
- 6 to 9 PM72%
329 flights · avg delay 24 min
Best day: Tuesday (82%). Worst: Monday (74%).
On time by month
All airlines, Jun 2023 to May 2026. Several years per month, so one stormy season doesn't define a month. Travel-month estimates use this seasonal pattern.
What delays this route
- Late-arriving aircraft54%
- Airline (crew, maintenance, boarding)27%
- Air traffic control and airport volume12%
- Severe weather6%
Share of delay minutes by the cause airlines report to the US DOT.
Historical odds, not a guarantee. Built from the US DOT Bureau of Transportation Statistics on-time reports (Jun 2025 to May 2026), FAA ground stop and delay program advisories, and 20 years of airport weather observations. Covers US airlines that report to the DOT; schedules are flights operated recently, so confirm times when you book. ATIS Alerts is not affiliated with any airline. Fares are what Aviasales travelers saw in recent searches (USD, one way, 1 adult), not live quotes; the partner site shows the current price. Fare links go to our travel partner and may earn us a commission at no cost to you. Affiliate disclosure
BWI to GSP questions
- What time of day is best to fly BWI to GSP?
- 9 AM to noon: 93% of flights arrived on time, against 72% for departures 6 to 9 PM.
- Which airline is most on time from BWI to GSP?
- Southwest, with a season-adjusted 81% chance of operating and arriving on time over 720 flights. The adjustment compares each airline with what the route did in the months it flew, so a carrier that skipped a stormy month gets no free credit.
- What is the worst month for delays on BWI to GSP?
- July (65% on time); the best was November (88%), averaged over Jun 2023 to May 2026.
- Is this a prediction for my flight?
- No. These are historical odds from the US DOT on-time reports, FAA advisories and airport weather records. Check your flight status and the FAA delay board on the day you fly.
More routes from BWI
- GSP to BWI (return)
- BWI to ATL 79%
- BWI to MCO 75%
- BWI to BOS 74%
- BWI to FLL 75%
- BWI to CLT 80%
- BWI to DEN 76%
- BWI to TPA 79%
- BWI to ORD 75%
- BWI to MIA 74%
- BWI to DTW 81%
- BWI to PVD 78%
- BWI to BNA 80%
Live status: FAA delays and ground stops