Flight number record

DL 871

Delta Air Lines · Salt Lake City to Seattle

Route: SLC → SEA
Departs: 17:10
Flights: 332
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 2026, not live status. For today’s DL 871, check with Delta Air Lines.

DL 871 lands a B+, 5 points better than the national rate of 77.6%. About one flight in six arrives 15 minutes late or worse, and those flights are late by about an hour on average. That is a workable record, not a spotless one. That rests on 332 flights, with a median arrival 8 minutes early.

Set against the rest of the country, DL 871's record is 5 points better than the US average of 77.6%. That gap is worth roughly 45 fewer late arrivals for every thousand flights.

On time

82.1%

Arrivals under 15 minutes late, of 330 completed flights

Avg delay

56 min

Across delayed arrivals only, not all flights

Cancelled

0.60%

National rate is 1.81%

1 hour+ late

4.8%

National rate is 8.1%

These figures cover 332 flights between July 2025 and June 2026. The median arrival is 8 minutes early, which is the part an average hides: most flights here are fine, and the on-time rate is decided by a tail of badly late ones. On-time means under 15 minutes late, the DOT's own threshold.

Schedule

When DL 871 flies

DL 871 flies SLC to SEA without a single fixed slot. Its most common scheduled departure was 17:10, used on 215 of 332 flights, with 17:20 (34 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.

Departs 17:10215 flights64.8%
Departs 17:2034 flights10.2%

Scale runs 0% to 100%. Rows with fewer than 30 flights show a dash.

Share of scheduled departures at each local time. Times used on fewer than one flight in ten are not listed.

A 17:10 departure sits in the 5pm–8pm window. Across every US flight scheduled in that window the on-time rate is 68.2%, and DL 871 runs 14 points better at 82.1%. By that time of day most aircraft have flown several legs already, and whatever went wrong earlier is still in the schedule.

Against the route

DL 871 next to SLC to SEA

Every carrier on SLC to SEA combined arrived on time 80.2% of the time across 4,108 flights, so DL 871 is 2 points ahead of it. Delta flew 2,222 flights on the same city pair under all its flight numbers, including this one, and those ran 83.3% on time. Across its whole network Delta Air Lines managed 81.6%, close to this flight's figure.

DL 871 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
DL 871thin sample	332	82.1%	56 min	0.60%	B+
All Delta Air Lines on SLC–SEA	2,222	83.3%	54 min	0.54%	B+
All carriers on SLC–SEA	4,108	80.2%	53 min	0.97%	B+
Delta Air Lines, whole network	1,038,570	81.6%	71 min	1.62%	B

Across the year

DL 871 quarter by quarter

Quarter by quarter DL 871 held fairly steady: 84.8% in Jul–Sep 2025, 77.3% in Oct–Dec 2025, 86.5% in Jan–Mar 2026 and 79.8% in Apr–Jun 2026. A spread of 9 points is about what a sample of this size moves on its own, so the annual figure is a fair summary.

Jul–Sep 202592 flights84.8%
Oct–Dec 202576 flights77.3%
Jan–Mar 202675 flights86.5%
Apr–Jun 202689 flights79.8%

Scale runs 70% to 90%. Rows with fewer than 30 flights show a dash.

By weekday, DL 871 did best on Monday at 88.2% on time and worst on Friday at 76.0%. Each day rests on about 47 flights, so a gap of 12 points is worth noticing but could still narrow in another year.

Delay causes

Why DL 871 runs late

One category carries most of the weight here. Carrier accounts for 51% of the 3,282 delay minutes carriers reported, and the remaining four split what is left. The split is by minutes rather than by flights, so a few very long delays count for as much as many short ones.

Carrier
51%
Late-arriving aircraft
31%
National Airspace System
11%
Extreme weather
7%

The largest share of delay minutes, 51%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 1,687 of the 3,282 delay minutes reported here. The split is drawn from 3,282 delay minutes reported on DL 871.

Cancellations are rare at 0.60%, below the national 1.81% and low enough to earn the plus on the grade. Roughly one flight in 100 is called off; the risk here is arriving late, not not arriving.

Connections and routes

What a delay on this flight costs

Badly late arrivals are rare here: only 4.8% land an hour or more behind schedule, against 8.1% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.

The 689 miles between these two airports put this in the middle of the US network, around two and a half to three hours of block time. That is enough cruise to absorb a ten-minute late pushback and not enough to absorb thirty. It is also long enough that the aircraft usually flies three or four legs a day rather than six, which slows how fast delay compounds.

Every one of the 332 flights under DL 871 in the data flew SLC to SEA. The number was not reused on any other city pair, which makes this a clean record of one route.

One caution: this is a thin sample. 332 flights over twelve months is enough to clear this site's floor but not enough to pin the rate down tightly, and a single bad week moves it by more than a point. Treat the grade as a rough reading.

What to do with this

Booking DL 871

For a booking, read DL 871 as 82.1% on time with 0.60% cancelled over 332 flights. Those are rates from the past twelve months, not a forecast for any particular day.

Where to go next

A flight number here means Delta Air Lines’s own number as it reports to the DOT. How the figures are computed is on the methodology page.

Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.

Key figures