Flight number record

DL 1597

Delta Air Lines · St. Louis to Minneapolis

Route: STL → MSP
Departs: 06:00
Flights: 365
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 2026, not live status. For today’s DL 1597, check with Delta Air Lines.

DL 1597 earns an A. Close to nine flights in ten arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 12 points better than the national rate of 77.6%. When something does go wrong the average delay runs an hour and a half. That rests on 365 flights, with a median arrival 13 minutes early.

Set against the rest of the country, DL 1597's record is 12 points better than the US average of 77.6%. That gap is worth roughly 124 fewer late arrivals for every thousand flights.

On time

90.0%

Arrivals under 15 minutes late, of 360 completed flights

Avg delay

93 min

Across delayed arrivals only, not all flights

Cancelled

1.37%

National rate is 1.81%

1 hour+ late

3.6%

National rate is 8.1%

These figures cover 365 flights between July 2025 and June 2026. The median arrival is 13 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 1597 flies

DL 1597 flies STL to MSP without a single fixed slot. Its most common scheduled departure was 06:00, used on 131 of 365 flights, with 06:10 (62 flights) and 06:21 (55 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.

Departs 06:00131 flights35.9%
Departs 06:1062 flights17.0%
Departs 06:2155 flights15.1%

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 06:00 departure sits in the 5am–8am window. Across every US flight scheduled in that window the on-time rate is 89.3%, and DL 1597 runs level with that at 90.0%. Early departures usually start with an aircraft that has not flown yet that day, which is most of why the window does well.

Against the route

DL 1597 next to STL to MSP

Every carrier on STL to MSP combined arrived on time 79.8% of the time across 1,896 flights, so DL 1597 is 10 points ahead of it. Delta flew 886 flights on the same city pair under all its flight numbers, including this one, and those ran 84.1% on time. Across its whole network Delta Air Lines managed 81.6%, which this flight beats by 8 points.

DL 1597 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
DL 1597	365	90.0%	93 min	1.37%	A
All Delta Air Lines on STL–MSP	886	84.1%	90 min	1.13%	B
All carriers on STL–MSP	1,896	79.8%	78 min	0.95%	B+
Delta Air Lines, whole network	1,038,570	81.6%	71 min	1.62%	B

Across the year

DL 1597 quarter by quarter

Quarter by quarter DL 1597 held fairly steady: 88.9% in Jul–Sep 2025, 85.9% in Oct–Dec 2025, 93.2% in Jan–Mar 2026 and 92.2% in Apr–Jun 2026. A spread of 7 points is about what a sample of this size moves on its own, so the annual figure is a fair summary.

Jul–Sep 202592 flights88.9%
Oct–Dec 202592 flights85.9%
Jan–Mar 202690 flights93.2%
Apr–Jun 202691 flights92.2%

Scale runs 75% to 100%. Rows with fewer than 30 flights show a dash.

By weekday, DL 1597 ranged from 85.7% on Monday to 96.2% on Friday. With about 52 flights behind each day, a spread of 11 points is inside normal variation, so the day you fly is not worth changing for this flight.

Delay causes

Why DL 1597 runs late

One category carries most of the weight here. Carrier accounts for 76% of the 3,358 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
76%
Late-arriving aircraft
12%
National Airspace System
8%
Extreme weather
4%

The largest share of delay minutes, 76%, 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 2,545 of the 3,358 delay minutes reported here. The split is drawn from 3,358 delay minutes reported on DL 1597.

Cancellations sit at 1.37% against a national 1.81%, which is ordinary. Diversions add another 0.00%.

Connections and routes

What a delay on this flight costs

Badly late arrivals are rare here: only 3.6% 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.

Every one of the 365 flights under DL 1597 in the data flew STL to MSP. 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. 365 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 1597

For a booking, DL 1597 has one of the better records a US domestic flight can show: 90.0% on time and 1.37% cancelled. That is a base rate, not a promise about any single 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