Flight number record
DL 1206
Delta Air Lines · Atlanta to Milwaukee
- Route
- ATL → MKE
- Departs
- 18:59
- Flights
- 319
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s DL 1206, check with Delta Air Lines.
DL 1206 sits in the middle of the pack with a C. Close to three flights in four arrive on time by the DOT's definition, 3 points worse than the national rate of 77.3%. The late ones land about 50 minutes behind schedule. That rests on 319 flights, with a median arrival 3 minutes early.
Key figures
On time
74.4%
Arrivals under 15 minutes late, of 312 completed flights
Avg delay
50 min
Across delayed arrivals only, not all flights
Cancelled
1.25%
National rate is 1.89%
1 hour+ late
7.1%
National rate is 8.3%
These figures cover 319 flights between September 2025 and August 2026. The median arrival is 3 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.
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Schedule
When DL 1206 flies
DL 1206 flies ATL to MKE without a single fixed slot. Its most common scheduled departure was 18:59, used on 46 of 319 flights, with 19:35 (35 flights) and 19:43 (34 flights) next.
- Departs 18:5946 flights14.4%
- Departs 19:3535 flights11.0%
- Departs 19:4334 flights10.7%
Scale runs 0% to 100%.
Share of scheduled departures at each local time. Times used on fewer than one flight in ten are not listed.
A 18:59 departure sits in the 5pm–8pm window. Across every US flight scheduled in that window the on-time rate is 68.0%, and DL 1206 runs 6 points better at 74.4%. By that time of day most aircraft have flown several legs already, and whatever went wrong earlier is still in the schedule.
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Against the route
DL 1206 next to ATL to MKE
Every carrier on ATL to MKE combined arrived on time 82.8% of the time across 2,264 flights, so DL 1206 is 8 points behind it. Delta flew 2,202 flights on the same city pair under all its flight numbers, including this one, and those ran 83.7% on time. Across its whole network Delta Air Lines managed 81.1%, which this flight trails by 7 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| DL 1206thin sample | 319 | 74.4% | 50 min | 1.25% | C |
| All Delta Air Lines on ATL–MKE | 2,202 | 83.7% | 53 min | 1.95% | B |
| All carriers on ATL–MKE | 2,264 | 82.8% | 53 min | 1.90% | B |
| Delta Air Lines, whole network | 1,039,517 | 81.1% | 71 min | 1.74% | B |
Across the year
DL 1206 quarter by quarter
DL 1206 did not run the same all year. Its best quarter was Jul–Sep 2025 at 83.3% on time and its weakest Jul–Sep 2026 at 68.3%, a swing of 15 points on roughly 64 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 202530 flights83.3%
- Oct–Dec 202591 flights78.9%
- Jan–Mar 202666 flights71.9%
- Apr–Jun 202671 flights72.1%
- Jul–Sep 202661 flights68.3%
Scale runs 60% to 90%.
By weekday, DL 1206 did best on Wednesday at 87.8% on time and worst on Friday at 59.1%. Each day rests on about 46 flights, so a gap of 29 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late DL 1206 runs when it is late
The 80 late arrivals split 35 under half an hour, 23 between 30 and 60 minutes, and 22 an hour or more.
- 15+ min early43 flights13.8%
- Within 15 min189 flights60.6%
- 15–29 min late35 flights11.2%
- 30–59 min late23 flights7.4%
- 1–2 hours late16 flights5.1%
- 2+ hours late6 flights1.9%
Scale runs 0% to 100%.
Share of 312 completed flights by arrival against schedule.
Time lost at the gate mostly stays lost. Of 63 departures that left 15 minutes late or more, only 6 made it up before arrival. In the other direction, 23 flights left on time yet arrived 15 minutes late or more, so that delay built up after pushback: in the air, in a holding pattern or on the ground at MKE.
The worst days
Worst days for DL 1206
The latest arrival of the period was on 7 December 2025, 4 hours 9 minutes behind schedule; most of its delay minutes were filed as extreme weather. The five worst days are spread across December, March, July, October and June, with no single month standing out.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 7 December 2025 | 4 hours 9 minutes | Extreme weather |
| 7 March 2026 | 3 hours 31 minutes | Carrier |
| 19 July 2026 | 3 hours 11 minutes | Late-arriving aircraft |
| 10 October 2025 | 2 hours 33 minutes | Carrier |
| 14 June 2026 | 2 hours 8 minutes | Late-arriving aircraft |
Delay causes
Why DL 1206 runs late
Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 3,970 reported delay minutes.
- 41%Carrier
- 27%National Airspace System
- 24%Late-arriving aircraft
- 8%Extreme weather
The largest share of delay minutes, 41%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 1,619 of the 3,970 delay minutes reported here. The split is drawn from 3,970 delay minutes reported on DL 1206.
Cancellations sit at 1.25% against a national 1.89%, which is ordinary. Diversions add another 0.94%.
Connections and routes
What a delay on this flight costs
7.1% of arrivals land an hour or more late, close to the national 8.3%, so a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last about 50 minutes, 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.
The same number turns up on one other city pair in the data, including MKE to ATL (103), but none flew often enough under DL 1206 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to ATL to MKE only.
One caution: this is a thin sample. 319 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 1206
For a booking, DL 1206 is one of the weaker ways to fly ATL to MKE: 8 points below the route as a whole. If the schedule allows, compare it with the other departures listed on the route page before settling on this one.
Related
Where to go next
- ATL to MKE, every carrier and departure
- MKE to ATL, the return direction
- Delta Air Lines 1268 on the same route80.9%
- Delta Air Lines 2999 on the same route91.6%
- Delta Air Lines 1151 on the same route88.6%
- Delta Air Lines 2152 on the same route83.6%
- Delta Air Lines 1246 on the same route89.4%
- Hartsfield-Jackson Atlanta International (ATL) delay statistics
- Milwaukee Mitchell International (MKE) delay statistics
- Delta Air Lines on-time record
- Every Delta Air Lines flight number with a record
- The most and least reliable flight numbers in the US
- Worst months to fly in the US, ranked by the data
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, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.