Airport month record

INDSEP

Indianapolis International in September 2025

Departures: 3,742
Month: September 2025
National, same month: 83.4%
Carriers: 11

Historical statistics for September 2025, not live status or a forecast for this year’s September. For today’s conditions at IND, see live FAA status.

IND in September earns an A+. More than four flights in five arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 2 points better than the national rate of 83.4%. When something does go wrong the average delay runs about an hour. That rests on 3,742 flights, of which Delta Air Lines flew 403 at 93.0% on time.

Delta Air Lines is the most reliable of the four carriers covered here at 93.0% on time across 403 flights.

On time

85.1%

Arrivals under 15 minutes late, of 3,715 completed departures

Avg delay

68 min

Across delayed arrivals only, not all flights

Cancelled

0.56%

Nationally in September: 0.51%

Whole year

80.2%

IND across all twelve months

These figures cover 3,742 departures from Indianapolis International in September 2025. On time means an arrival less than 15 minutes after the scheduled gate time, the DOT's threshold, and the national comparison uses every US departure in the same month rather than the whole year.

Against the year

September next to IND's other months

Against IND's own year, September ran 5 points better than the twelve-month rate of 80.2%, which makes it the best of the twelve months in the data. Cancellations were unusually low for IND in September, at 0.56% against 1.91% across the year. Either side of it, August ran 81.4% on time and October 83.2%, so a trip moved by a few weeks would have landed in a worse stretch.

IND month by month
Month	Flights	On time	Avg delay	Cancelled	Grade
July 2025	4,222	74.9%	85 min	3.01%	C−
August 2025	3,876	81.4%	78 min	1.11%	B
September 2025 (this page)	3,742	85.1%	68 min	0.56%	A+
October 2025	4,354	83.2%	70 min	0.57%	B+
November 2025	3,904	83.1%	77 min	2.84%	B
December 2025	3,906	69.5%	75 min	1.59%	C
January 2026	3,690	79.7%	78 min	4.44%	B−
February 2026	3,457	83.3%	61 min	2.57%	B
March 2026	4,362	76.7%	87 min	2.57%	B
April 2026	4,290	83.0%	65 min	1.19%	B
May 2026	4,324	82.5%	62 min	0.88%	B+
June 2026	4,249	79.9%	76 min	1.88%	B

Departure window

The best time of day to leave IND in September

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 24 points, against 11 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am984 flights93.8%
8am–11am617 flights91.7%
11am–2pm590 flights87.8%
2pm–5pm691 flights78.6%
5pm–8pm712 flights74.4%
8pm–5am148 flights69.4%

Scale runs 60% to 100%. Rows with fewer than 30 flights show a dash.

Book the early departure. Flights leaving between 5am–8am arrive on time 93.8% of the time, against 69.4% for the overnight window. That is 24 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 5am–8am window is the busiest, with 984 flights scheduled in it.

Across the week, Tuesday is the strongest day at 88.0% on time and Thursday the weakest at 82.6%. 5 points is a smaller lever than departure hour, but it is free.

Carrier by carrier

Which airlines ran best at IND in September

The choice of carrier is not cosmetic here. Delta Air Lines arrives on time 93.0% of the time; American Airlines manages 82.0%. Sample sizes sit next to every figure, because a two-point gap across 521 flights means less than a ten-point one.

Carriers at IND in September 2025
Airline	Flights	On time	Avg delay	Cancelled	Grade
Republic Airways	1,074	84.8%	68 min	0.65%	B+
Southwest Airlines	834	83.4%	49 min	0.00%	B+
American Airlines	521	82.0%	84 min	1.54%	B
Delta Air Lines	403	93.0%	71 min	0.25%	A+
United Airlinesthin sample	272	83.8%	71 min	0.00%	B+
Spirit Airlinesthin sample	196	90.3%	146 min	0.51%	A+
SkyWest Airlinesthin sample	145	91.7%	33 min	0.69%	A+
Envoy Airthin sample	103	76.2%	88 min	1.94%	B
Frontier Airlinesthin sample	71	74.6%	50 min	0.00%	C+
Allegiant Airthin sample	64	93.7%	110 min	0.00%	A+
Alaska Airlinesthin sample	51	74.5%	26 min	0.00%	C+

Delta leads American by 11 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.

Route by route

Busiest routes out of IND in September

Routes from IND in September 2025
Route	Flights	On time	Avg delay	Cancelled	Grade
IND to ORD · Chicago	391	82.0%	71 min	0.51%	B+
IND to ATL · Atlantathin sample	278	94.6%	42 min	0.00%	A+
IND to LGA · New Yorkthin sample	218	88.0%	44 min	0.00%	A+
IND to DEN · Denverthin sample	213	82.2%	57 min	0.00%	B+
IND to DFW · Dallas-Fort Worththin sample	200	81.5%	110 min	2.50%	B
IND to EWR · Newarkthin sample	199	89.8%	104 min	1.51%	A
IND to DCA · Washingtonthin sample	172	80.0%	55 min	1.16%	B
IND to BOS · Bostonthin sample	160	60.9%	60 min	2.50%	D
IND to MCO · Orlandothin sample	151	84.1%	53 min	0.00%	B+
IND to CLT · Charlottethin sample	148	87.1%	54 min	0.00%	A+
IND to MSP · Minneapolisthin sample	107	82.1%	83 min	0.93%	B+
IND to PHL · Philadelphiathin sample	102	84.0%	45 min	1.96%	B
IND to LAS · Las Vegasthin sample	98	82.5%	48 min	0.00%	B+
IND to PHX · Phoenixthin sample	98	83.5%	107 min	0.00%	B+
IND to BWI · Baltimorethin sample	95	85.3%	86 min	0.00%	A+
IND to JFK · New Yorkthin sample	94	91.5%	86 min	0.00%	A+
IND to IAD · Washingtonthin sample	89	88.8%	118 min	0.00%	A+
IND to DTW · Detroitthin sample	82	95.1%	45 min	0.00%	A+
IND to FLL · Fort Lauderdalethin sample	79	84.6%	156 min	1.27%	B
IND to TPA · Tampathin sample	79	86.1%	75 min	0.00%	A+
IND to AUS · Austinthin sample	77	92.2%	42 min	0.00%	A+
IND to LAX · Los Angelesthin sample	64	87.3%	35 min	1.56%	A
IND to MDW · Chicagothin sample	60	88.3%	46 min	0.00%	A+
IND to IAH · Houstonthin sample	60	93.3%	35 min	0.00%	A+
IND to MIA · Miamithin sample	52	78.8%	63 min	0.00%	B+

Delay causes

What held IND up in September

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 37,000 reported delay minutes.

National Airspace System
37%
Late-arriving aircraft
36%
Carrier
27%
Extreme weather
0%
Security
0%

36% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. That is a cascade, and cascades start small and grow through the day. Across 37,000 reported delay minutes here, that single category outweighs weather by 36 to one. It is the strongest argument for booking the first departure of the morning, when the aircraft has been sitting at the gate overnight with nothing to inherit. The split is drawn from 37,473 reported delay minutes.

Cancellations are rare at 0.56%, below the national 0.51% and low enough to earn the plus on the grade. Roughly one flight in 100 is called off; the risk here is arriving late, not not arriving.

Badly late arrivals are rare here: only 4.4% land an hour or more behind schedule, against 5.4% 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.

What to do with this

Flying from IND in September

For a September trip through IND: this is one of the better months to be flying from here, 85.1% on time with 0.56% cancelled. That is a base rate for the month as a whole; a single storm can still spoil a particular day.

Indianapolis International (IND), the whole year
IND in July74.9%
IND in August81.4%
IND in October83.2%
IND in November83.1%
IND in December69.5%
IND in January79.7%
IND in February83.3%
IND in March76.7%
IND in April83.0%
IND in May82.5%
IND in June79.9%

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