Airport month record
LASSEP
Harry Reid International in September 2025
- Departures
- 14,399
- 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 LAS, see live FAA status.
LAS in September lands a B+, 5 points worse than the national rate of 83.4%. About one flight in five arrives 15 minutes late or worse, and those flights are late by about an hour on average. That rests on 14,399 flights, of which Delta Air Lines flew 1,250 at 84.4% on time.
Delta Air Lines is the most reliable of the nine carriers covered here at 84.4% on time across 1,250 flights.
Key figures
On time
78.8%
Arrivals under 15 minutes late, of 14,285 completed departures
Avg delay
66 min
Across delayed arrivals only, not all flights
Cancelled
0.53%
Nationally in September: 0.51%
Whole year
76.9%
LAS across all twelve months
These figures cover 14,399 departures from Harry Reid 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 LAS's other months
Against LAS's own year, September ran 2 points better than the twelve-month rate of 76.9%, which makes it number five of twelve months, best first. Cancellations were unusually low for LAS in September, at 0.53% against 0.90% across the year.
| Month | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| September 2025 (this page) | 14,399 | 78.8% | 66 min | 0.53% | B+ |
| October 2025 | 15,597 | 77.1% | 62 min | 0.31% | B+ |
| November 2025 | 14,443 | 79.5% | 59 min | 1.73% | B |
| December 2025 | 14,547 | 79.9% | 59 min | 0.60% | B+ |
| January 2026 | 13,695 | 83.1% | 65 min | 1.86% | B |
| February 2026 | 12,886 | 83.1% | 58 min | 0.88% | B+ |
| March 2026 | 15,169 | 78.3% | 60 min | 1.15% | B |
| April 2026 | 14,672 | 78.8% | 54 min | 0.40% | B+ |
| May 2026 | 14,585 | 74.1% | 60 min | 0.67% | C+ |
| June 2026 | 13,704 | 70.7% | 61 min | 0.77% | C+ |
| July 2026 | 14,315 | 69.6% | 63 min | 1.01% | C |
| August 2026 | 13,832 | 69.6% | 72 min | 0.95% | C+ |
Departure window
The best time of day to leave LAS in September
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 26 points, against 8 points between the best and worst carrier.
- 5am–8am2,101 flights92.5%
- 8am–11am3,239 flights87.2%
- 11am–2pm2,668 flights77.2%
- 2pm–5pm2,327 flights69.4%
- 5pm–8pm1,993 flights66.6%
- 8pm–5am2,071 flights76.0%
Scale runs 60% to 100%.
Book the early departure. Flights leaving between 5am–8am arrive on time 92.5% of the time, against 66.6% for the evening window. That is 26 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 8am–11am window is the busiest, with 3,239 flights scheduled in it.
Across the week, Wednesday is the strongest day at 90.0% on time and Friday the weakest at 61.3%, a spread of 29 points.
Carrier by carrier
Which airlines ran best at LAS in September
The choice of carrier is not cosmetic here. Delta Air Lines arrives on time 84.4% of the time; Alaska Airlines manages 76.1%. Sample sizes sit next to every figure, because a two-point gap across 441 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Southwest Airlines | 6,794 | 76.7% | 53 min | 0.47% | B+ |
| Spirit Airlines | 1,344 | 81.3% | 91 min | 1.12% | B |
| Delta Air Lines | 1,250 | 84.4% | 76 min | 0.00% | B+ |
| United Airlines | 1,194 | 80.5% | 60 min | 0.17% | B+ |
| American Airlines | 1,105 | 84.4% | 101 min | 1.09% | B |
| Frontier Airlines | 934 | 78.6% | 81 min | 0.75% | B+ |
| Allegiant Air | 532 | 80.0% | 77 min | 0.00% | B+ |
| Alaska Airlines | 441 | 76.1% | 52 min | 0.45% | B+ |
| SkyWest Airlines | 380 | 76.3% | 68 min | 0.79% | B+ |
| JetBlue Airwaysthin sample | 275 | 72.3% | 76 min | 1.09% | C |
| Hawaiian Airlinesthin sample | 150 | 74.7% | 118 min | 0.00% | C+ |
Delta leads Alaska by 8 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.
Route by route
Busiest routes out of LAS in September
| Route | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| LAS to LAX · Los Angeles | 691 | 78.2% | 55 min | 0.43% | B+ |
| LAS to SAN · San Diego | 610 | 72.5% | 71 min | 0.98% | C+ |
| LAS to DEN · Denver | 539 | 73.0% | 68 min | 0.19% | C+ |
| LAS to SFO · San Francisco | 513 | 63.2% | 44 min | 0.39% | D+ |
| LAS to ORD · Chicago | 481 | 77.6% | 91 min | 0.62% | B+ |
| LAS to SEA · Seattle | 441 | 82.4% | 60 min | 0.23% | B+ |
| LAS to PHX · Phoenix | 431 | 78.6% | 69 min | 2.09% | B |
| LAS to DFW · Dallas-Fort Worth | 423 | 85.9% | 101 min | 2.13% | A |
| LAS to SMF · Sacramento | 407 | 77.8% | 64 min | 0.25% | B+ |
| LAS to ATL · Atlanta | 389 | 88.4% | 87 min | 0.00% | A+ |
| LAS to SJC · San Jose | 375 | 79.0% | 51 min | 0.80% | B+ |
| LAS to BUR · Burbankthin sample | 352 | 79.1% | 63 min | 0.85% | B+ |
| LAS to SNA · Santa Anathin sample | 347 | 77.3% | 50 min | 1.15% | B |
| LAS to JFK · New Yorkthin sample | 336 | 80.1% | 68 min | 0.89% | B+ |
| LAS to RNO · Renothin sample | 323 | 81.3% | 63 min | 0.62% | B+ |
| LAS to SLC · Salt Lake Citythin sample | 314 | 78.9% | 62 min | 0.32% | B+ |
| LAS to OAK · Oaklandthin sample | 300 | 70.6% | 63 min | 0.33% | C+ |
| LAS to PDX · Portlandthin sample | 264 | 79.8% | 55 min | 0.00% | B+ |
| LAS to IAH · Houstonthin sample | 255 | 85.5% | 76 min | 0.00% | A+ |
| LAS to DTW · Detroitthin sample | 239 | 82.0% | 150 min | 0.00% | B+ |
| LAS to EWR · Newarkthin sample | 237 | 77.6% | 70 min | 0.84% | B+ |
| LAS to AUS · Austinthin sample | 218 | 78.5% | 75 min | 0.92% | B+ |
| LAS to MDW · Chicagothin sample | 212 | 82.9% | 66 min | 0.47% | B+ |
| LAS to ONT · Ontariothin sample | 201 | 77.6% | 49 min | 0.00% | B+ |
| LAS to DAL · Dallasthin sample | 197 | 82.1% | 72 min | 0.00% | B+ |
Delay causes
What held LAS 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 198,000 reported delay minutes.
- 40%Late-arriving aircraft
- 31%Carrier
- 25%National Airspace System
- 3%Extreme weather
- 0%Security
40% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 198,000 reported delay minutes here, that single category outweighs weather by 12 to one. The split is drawn from 198,402 reported delay minutes.
Cancellations are rare at 0.53%, 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.
6.8% of arrivals land an hour or more late, close to the national 5.4%, 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 an hour, which a normal layover absorbs.
What to do with this
Flying from LAS in September
For a September trip through LAS: expect 78.8% on time and 0.53% cancelled, going by September 2025. The 5am–8am window was the strongest part of the day.
Related
Where to go next
- Harry Reid International (LAS), the whole year
- LAS in October77.1%
- LAS in November79.5%
- LAS in December79.9%
- LAS in January83.1%
- LAS in February83.1%
- LAS in March78.3%
- LAS in April78.8%
- LAS in May74.1%
- LAS in June70.7%
- LAS in July69.6%
- LAS in August69.6%
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.