ON TIMEBOARD
Delta Air Lines / BOS → SDF

DL 5615 on time

Delta Air Lines 5615: Boston to Louisville at 9:55 a.m.; Louisville to Boston at 1:15 p.m. (past 12 months). Figures below the title are for BOS → SDF, its busiest leg

On time
83%
234 flights · likely 78–88%
Cancelled
2.6%
of scheduled flights
Typical arrival
−11 min
median vs schedule
When late
+53 min
average delay
Similar flights
83%
DL, same route & hour

About 1 in 6 DL 5615 flights from Boston arrived 15+ minutes late, diverted or cancelled over the past year (17%); 2.6% were cancelled. The typical flight landed 11 minutes early.

DL 5615: BOS → SDF

Scheduled to leave Boston at 9:55 a.m. local time, operated by Republic Airways as YX 5615. Over the past year it arrived on time 83% of the time (234 flights), in line with other DL flights on the route at that hour (83%). Last seen in the data Aug 31, 2026.

Month by month

40%70%100%Apr 2025: 92% on time (26 flights)92AprMay 2025: 86% on time (29 flights)86MayJun 2025: too few flights (7 flights)JunDec 2025: too few flights (9 flights)DecJan 2026: 64% on time (25 flights)64JanFeb 2026: 64% on time (22 flights)64FebMar 2026: 89% on time (27 flights)89MarApr 2026: 96% on time (28 flights)96AprMay 2026: 94% on time (31 flights)94MayJun 2026: 90% on time (30 flights)90JunJul 2026: 81% on time (31 flights)81JulAug 2026: 90% on time (31 flights)90Aug

By day of week

DayFlightsOn time
Monday3781%
Tuesday3683%
Wednesday3488%
Thursday3488%
Friday3681%
Saturday2383%
Sunday3479%

Why it was late

Airline (crew, maintenance, ops) 48%Air traffic & airport (NAS) 26%Late inbound plane 25%Severe weather 1%

All flights BOS → SDF · Connecting off DL 5615? Check the risk

DL 5615: SDF → BOS

Scheduled to leave Louisville at 1:15 p.m. local time, operated by Republic Airways as YX 5615. Over the past year it arrived on time 75% of the time (227 flights), in line with other DL flights on the route at that hour (73%). Last seen in the data Aug 31, 2026.

Month by month

40%70%100%Feb 2025: 77% on time (22 flights)77FebMar 2025: 88% on time (26 flights)88MarApr 2025: 81% on time (26 flights)81AprMay 2025: too few flights (5 flights)MayJan 2026: 68% on time (22 flights)68JanFeb 2026: 59% on time (22 flights)59FebMar 2026: 83% on time (30 flights)83MarApr 2026: 77% on time (30 flights)77AprMay 2026: 71% on time (31 flights)71MayJun 2026: 83% on time (30 flights)83JunJul 2026: 71% on time (31 flights)71JulAug 2026: 84% on time (31 flights)84Aug

By day of week

DayFlightsOn time
Monday3580%
Tuesday3479%
Wednesday3474%
Thursday3476%
Friday3474%
Saturday2568%
Sunday3174%

Why it was late

Air traffic & airport (NAS) 48%Airline (crew, maintenance, ops) 34%Late inbound plane 15%Severe weather 3%

All flights SDF → BOS · Connecting off DL 5615? Check the risk

Questions

How often is DL 5615 from BOS to SDF late?

Delta Air Lines 5615 from Boston, MA to Louisville, KY arrived 15 or more minutes late, was diverted or was cancelled on 17% of 234 scheduled flights between September 2025 and August 2026. 2.6% were cancelled.

How often is DL 5615 from SDF to BOS late?

Delta Air Lines 5615 from Louisville, KY to Boston, MA arrived 15 or more minutes late, was diverted or was cancelled on 25% of 227 scheduled flights between September 2025 and August 2026. 3.1% were cancelled.

Flight numbers change. Figures cover flights with this airline, number and route only. "Likely range" is the 95% interval for the true on-time rate given the number of flights. This is history, not live status: check Delta Air Lines for today's flight. Method.