Carrier route record

DLSLC→BWI

Delta Air Lines · Salt Lake City to Baltimore

Flights: 360
Period: July 2025 to June 2026
Share of route: 47%
Carriers: 2

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

Delta on SLC to BWI lands a B, level with the national rate of 77.6%. Roughly one flight in five arrives 15 minutes late or worse, and those flights are late by about 35 minutes on average. That is a workable record, not a spotless one. That rests on 360 flights, with a median arrival 1 minute late.

The US average over the same twelve months is 77.6%, so there is little to separate Delta on SLC to BWI from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.

On time

77.9%

Arrivals under 15 minutes late, of 353 completed flights

Avg delay

35 min

Across delayed arrivals only, not all flights

Cancelled

1.67%

National rate is 1.81%

Whole route

80.4%

Every carrier on SLC to BWI, 770 flights

These figures cover 360 flights between July 2025 and June 2026. On-time means an arrival less than 15 minutes after the scheduled gate time, the same threshold the Department of Transportation uses in its own reports. Cancelled and diverted flights are excluded from the on-time rate and counted separately, which is why the cancellation column matters on its own.

Carrier by carrier

Delta against every carrier on SLC to BWI

Delta flew 360 of the 770 flights on SLC to BWI, about 47% of it. Its 77.9% on time is 3 points worse than the route as a whole, which runs 80.4%. Ranked by on-time rate it is last of two carriers on the route, where the range runs from Southwest at 82.6% to Delta at 77.9%.

Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.

On-time performance by carrier on SLC to BWI
Airline	Flights	On time	Avg delay	Cancelled	Grade
Southwest Airlines	410	82.6%	57 min	1.22%	B
Delta Air Lines (this page)thin sample	360	77.9%	35 min	1.67%	B

Flight by flight

Delta flight numbers on SLC to BWI

DL 207923:4077.9% · 360 flights

Departure window

When Delta runs best on this route

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 11 points, against half a point between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am—
8am–11am—
11am–2pm—
2pm–5pm—
5pm–8pm83 flights86.1%
8pm–5am277 flights75.5%

Scale runs 65% to 90%. Rows with fewer than 30 flights show a dash.

The 5pm–8pm window is the strongest at 86.1% on time. The full set of windows spans 11 points.

Across the year

Delta on SLC to BWI through the year

Jul–Sep 202592 flights92.4%
Oct–Dec 202587 flights75.3%
Jan–Mar 202690 flights83.7%
Apr–Jun 202691 flights60.0%

Scale runs 50% to 100%. Rows with fewer than 30 flights show a dash.

Monthly volumes are too low here to break the year into twelve reliable readings. What the twelve-month total says is 77.9% on time across 360 flights.

Delta on SLC to BWI did not run the same all year. Its best quarter was Jul–Sep 2025 at 92.4% on time and its weakest Apr–Jun 2026 at 60.0%, a swing of 32 points on roughly 90 flights a quarter. The twelve-month rate averages over that, so if you are flying in a weak quarter the quarter's own figure is the better guide.

Across the week, Saturday is the strongest day at 86.3% on time and Friday the weakest at 64.7%. 22 points is a smaller lever than departure hour, but it is free.

Delay causes

Why Delta runs late on this route

One category carries most of the weight here. National Airspace System accounts for 46% of the 2,723 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.

National Airspace System
46%
Carrier
42%
Late-arriving aircraft
13%

46% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 1,246 minutes out of 2,723, against a national NAS share of 21%. The split is drawn from 2,723 reported delay minutes.

The largest share of delay minutes, 42%, 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 1,130 of the 2,723 delay minutes reported here.

Cancellations sit at 1.67% against a national 1.81%, which is ordinary. Diversions add another 0.28%.

Connections and stage length

What a delay here costs

Badly late arrivals are rare here: only 2.3% 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.

At 1,865 miles this is transcontinental flying, and long routes get a quiet structural advantage. Scheduled block time on a flight this length carries more padding in absolute minutes, so a twenty-minute late departure often still becomes an on-time arrival. Read the on-time rate here as slightly flattering next to a short-haul route with the same operational quality.

The return leg runs 80.2% on time across 360 flights, within 2 points of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.

One caution: this is a thin sample. 360 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 Delta on SLC to BWI

Put together: treat all of this as provisional. 360 flights over twelve months is enough to clear this site's floor and not enough to be confident to better than a couple of points. The 77.9% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 353 completed flights over 12 months sit behind that.

Where to go next

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