Carrier route record

DLDTW→MIA

Delta Air Lines · Detroit to Miami

Flights: 929
Period: September 2025 to August 2026
Share of route: 53%
Carriers: 6

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

Delta on DTW to MIA lands a B, 2 points better than the national rate of 77.3%. About one flight in five arrives 15 minutes late or worse, and those flights are late by about 55 minutes on average. That rests on 929 flights, with a median arrival 6 minutes early.

The US average over the same twelve months is 77.3%, so there is little to separate Delta on DTW to MIA from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.

On time

79.1%

Arrivals under 15 minutes late, of 917 completed flights

Avg delay

55 min

Across delayed arrivals only, not all flights

Cancelled

1.08%

National rate is 1.89%

Whole route

80.7%

Every carrier on DTW to MIA, 1,757 flights

These figures cover 929 flights between September 2025 and August 2026. The median arrival is 6 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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Carrier by carrier

Delta against every carrier on DTW to MIA

Delta flew 929 of the 1,757 flights on DTW to MIA, most of the route. Its 79.1% on time is 2 points worse than the route as a whole, which runs 80.7%. Ranked by on-time rate it is number three of six carriers on the route, where the range runs from American at 88.9% to Frontier at 66.7%. Four of those carriers flew fewer than 365 flights here, so treat their positions as rough.

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 DTW to MIA
Airline	Flights	On time	Avg delay	Cancelled	Grade
American Airlines	394	88.9%	84 min	1.02%	A
Envoy Airthin sample	108	81.5%	72 min	0.00%	B+
Delta Air Lines (this page)	929	79.1%	55 min	1.08%	B
Spirit Airlinesthin sample	248	77.7%	61 min	4.03%	B−
Republic Airwaysthin sample	14	71.4%	39 min	0.00%	C+
Frontier Airlinesthin sample	64	66.7%	96 min	1.56%	C

Flight by flight

Delta flight numbers on DTW to MIA

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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 18 points, against half a point between the best and worst carrier.

5am–8am154 flights79.1%
8am–11am210 flights91.3%
11am–2pm82 flights73.2%
2pm–5pm239 flights74.6%
5pm–8pm230 flights77.3%
8pm–5am14 flights—

Scale runs 65% to 95%. Rows with fewer than 30 flights show a dash.

The weak window here is the middle of the day, not the evening: 11am–2pm runs 73.2% on time against 91.3% for 8am–11am. That shape usually means a departure bank rather than an accumulating delay, so the recovery later in the afternoon is real rather than noise. The 2pm–5pm window is the busiest, with 239 flights scheduled in it.

Across the year

Delta on DTW to MIA through the year

Darker means more delays. Figures are on-time percentages.August best, December worst

December is the weak month at 58.4% on time, against 90.2% in August. Winter delays cluster: a single storm system can account for most of a month's shortfall, so an average December hides both very good weeks and genuinely unflyable days. January was the busiest month here, with 93 flights.

Across the week, Tuesday is the strongest day at 90.9% on time and Sunday the weakest at 65.4%, a spread of 26 points.

Arrival by arrival

How late Delta on DTW to MIA runs when it is late

Delta on DTW to MIA often beats the schedule: 258 of 917 completed flights, 28%, arrived 15 minutes or more early. The 192 late arrivals split 67 under half an hour, 64 between 30 and 60 minutes, and 61 an hour or more.

15+ min early258 flights28.1%
Within 15 min467 flights50.9%
15–29 min late67 flights7.3%
30–59 min late64 flights7.0%
1–2 hours late42 flights4.6%
2+ hours late19 flights2.1%

Scale runs 0% to 100%.

Share of 917 completed flights by arrival against schedule.

43 of 158 late departures made up the time and arrived on time, 27% of them. In the other direction, 77 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 MIA.

The worst days

Worst days for Delta on DTW to MIA

The latest arrival of the period was on 7 July 2026, 4 hours 58 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). The same cause led on three of the five worst days.

The latest arrivals of Delta on DTW to MIA in the period
Date	Arrived late by	Largest filed cause
7 July 2026	4 hours 58 minutes	Carrier
9 November 2025	4 hours 13 minutes	National Airspace System
24 January 2026	3 hours 26 minutes	Carrier
20 June 2026	3 hours 16 minutes	Carrier
16 March 2026	2 hours 57 minutes	National Airspace System

Delay causes

Why Delta runs late on this route

Carrier accounts for 51% of the 11,000 delay minutes carriers reported here, and the remaining four split what is left.

Carrier
51%
National Airspace System
37%
Late-arriving aircraft
11%
Extreme weather
1%

37% 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 3,914 minutes out of 11,000, against a national NAS share of 21%. The split is drawn from 10,546 reported delay minutes.

The largest share of delay minutes, 51%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 5,367 of the 11,000 delay minutes reported here.

Cancellations sit at 1.08% against a national 1.89%, which is ordinary. Diversions add another 0.22%.

Connections and stage length

What a delay here costs

6.7% 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 55 minutes, which a normal layover absorbs.

The 1,145 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 return leg runs 76.9% on time across 930 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. 929 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 DTW to MIA

Put together: treat all of this as provisional. 929 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 79.1% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 917 completed flights over 12 months sit behind that.

Where to go next

Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated 22 October 2026; recomputed monthly. How this data is collected.

Key figures