Flight number record

DL 1236

Delta Air Lines · Milwaukee to Atlanta

Route: MKE → ATL
Departs: 07:00
Flights: 365
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 2026, not live status. For today’s DL 1236, check with Delta Air Lines.

DL 1236 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 close to two hours. That rests on 365 flights, with a median arrival 16 minutes early.

Set against the rest of the country, DL 1236's record is 12 points better than the US average of 77.6%. That gap is worth roughly 121 fewer late arrivals for every thousand flights.

On time

89.7%

Arrivals under 15 minutes late, of 358 completed flights

Avg delay

117 min

Across delayed arrivals only, not all flights

Cancelled

1.64%

National rate is 1.81%

1 hour+ late

5.3%

National rate is 8.1%

These figures cover 365 flights between July 2025 and June 2026. The median arrival is 16 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 1236 flies

DL 1236 flies MKE to ATL without a single fixed slot. Its most common scheduled departure was 07:00, used on 140 of 365 flights, with 07:05 (85 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.

Departs 07:00140 flights38.4%
Departs 07:0585 flights23.3%

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 07:00 departure sits in the 5am–8am window. Across every US flight scheduled in that window the on-time rate is 89.3%, and DL 1236 runs level with that at 89.7%. 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 1236 next to MKE to ATL

Every carrier on MKE to ATL combined arrived on time 89.4% of the time across 2,267 flights, so DL 1236 is about level with it. Delta flew 2,205 flights on the same city pair under all its flight numbers, including this one, and those ran 90.0% on time. Across its whole network Delta Air Lines managed 81.6%, which this flight beats by 8 points.

DL 1236 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
DL 1236	365	89.7%	117 min	1.64%	A
All Delta Air Lines on MKE–ATL	2,205	90.0%	96 min	1.90%	A
All carriers on MKE–ATL	2,267	89.4%	92 min	1.90%	A
Delta Air Lines, whole network	1,038,570	81.6%	71 min	1.62%	B

Across the year

DL 1236 quarter by quarter

DL 1236 did not run the same all year. Its best quarter was Jul–Sep 2025 at 95.7% on time and its weakest Jan–Mar 2026 at 80.2%, a swing of 16 points on roughly 91 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.

Jul–Sep 202592 flights95.7%
Oct–Dec 202592 flights87.8%
Jan–Mar 202690 flights80.2%
Apr–Jun 202691 flights94.4%

Scale runs 70% to 100%. Rows with fewer than 30 flights show a dash.

By weekday, DL 1236 ranged from 85.7% on Monday to 92.5% on Tuesday. With about 52 flights behind each day, a spread of 7 points is inside normal variation, so the day you fly is not worth changing for this flight.

Delay causes

Why DL 1236 runs late

One category carries most of the weight here. Carrier accounts for 67% of the 4,341 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
67%
National Airspace System
21%
Late-arriving aircraft
9%
Extreme weather
3%

The largest share of delay minutes, 67%, 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 2,890 of the 4,341 delay minutes reported here. The split is drawn from 4,341 delay minutes reported on DL 1236.

Cancellations sit at 1.64% against a national 1.81%, which is ordinary. Diversions add another 0.27%.

Connections and routes

What a delay on this flight costs

5.3% of arrivals land an hour or more late, close to the national 8.1%. That is the figure that decides a connection, and it says a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last close to two hours, which a normal layover absorbs.

The 669 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 365 flights under DL 1236 in the data flew MKE to ATL. 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 1236

For a booking, read DL 1236 as 89.7% on time with 1.64% cancelled over 365 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