ON TIMEBOARD

DL 571 on time

Delta Air Lines 571: Boston to San Diego at 5:10 p.m.; San Diego to Boston at 9:54 p.m. (past 12 months). Figures below the title are for BOS → SAN, its busiest leg

On time
64%
364 flights · likely 59–69%
Cancelled
1.7%
of scheduled flights
Typical arrival
+1 min
median vs schedule
When late
+44 min
average delay
Similar flights
64%
DL, same route & hour

About 1 in 3 DL 571 flights from Boston arrived 15+ minutes late, diverted or cancelled over the past year (36%); 1.7% were cancelled. The typical flight landed 1 minutes late.

DL 571: BOS → SAN

Scheduled to leave Boston at 5:10 p.m. local time. Over the past year it arrived on time 64% of the time (364 flights), in line with other DL flights on the route at that hour (64%). Last seen in the data Aug 31, 2026.

Month by month

40%70%100%Sep 2025: 50% on time (30 flights)50SepOct 2025: 55% on time (31 flights)55OctNov 2025: 62% on time (29 flights)62NovDec 2025: 74% on time (31 flights)74DecJan 2026: 52% on time (31 flights)52JanFeb 2026: 75% on time (28 flights)75FebMar 2026: 77% on time (31 flights)77MarApr 2026: 60% on time (30 flights)60AprMay 2026: 65% on time (31 flights)65MayJun 2026: 73% on time (30 flights)73JunJul 2026: 71% on time (31 flights)71JulAug 2026: 55% on time (31 flights)55Aug

By day of week

DayFlightsOn time
Monday5368%
Tuesday5263%
Wednesday5262%
Thursday5167%
Friday5258%
Saturday5265%
Sunday5265%

Why it was late

Air traffic & airport (NAS) 49%Late inbound plane 31%Airline (crew, maintenance, ops) 20%

All flights BOS → SAN · Connecting off DL 571? Check the risk

DL 571: SAN → BOS

Scheduled to leave San Diego at 9:54 p.m. local time. Over the past year it arrived on time 80% of the time (162 flights), better than other DL flights on the route at that hour (74%). Last seen in the data Aug 31, 2026.

Month by month

40%70%100%May 2025: too few flights (1 flights)MayJun 2025: 87% on time (23 flights)87JunJul 2025: 71% on time (31 flights)71JulAug 2025: 94% on time (31 flights)94AugSep 2025: 70% on time (30 flights)70SepOct 2025: too few flights (5 flights)OctFeb 2026: too few flights (7 flights)FebMar 2026: too few flights (3 flights)MarMay 2026: 88% on time (25 flights)88MayJun 2026: 90% on time (30 flights)90JunJul 2026: 77% on time (31 flights)77JulAug 2026: 77% on time (31 flights)77Aug

By day of week

DayFlightsOn time
Monday2277%
Tuesday2483%
Wednesday2479%
Thursday2273%
Friday2291%
Saturday2685%
Sunday2273%

Why it was late

Airline (crew, maintenance, ops) 51%Air traffic & airport (NAS) 36%Late inbound plane 13%

All flights SAN → BOS · Connecting off DL 571? Check the risk

Questions

How often is DL 571 from BOS to SAN late?

Delta Air Lines 571 from Boston, MA to San Diego, CA arrived 15 or more minutes late, was diverted or was cancelled on 36% of 364 scheduled flights between September 2025 and August 2026. 1.7% were cancelled.

How often is DL 571 from SAN to BOS late?

Delta Air Lines 571 from San Diego, CA to Boston, MA arrived 15 or more minutes late, was diverted or was cancelled on 20% of 162 scheduled flights between September 2025 and August 2026. 0.0% 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.