Airport month record
SEAJUL
Seattle-Tacoma International in July 2026
- Departures
- 16,214
- Month
- July 2026
- National, same month
- 71.7%
- Carriers
- 9
Historical statistics for July 2026, not live status or a forecast for this year’s July. For today’s conditions at SEA, see live FAA status.
SEA in July sits in the middle of the pack with a C+. About seven flights in ten arrive on time by the DOT's definition, level with the national rate of 71.7%. The late ones land about an hour behind schedule. That rests on 16,214 flights, of which SkyWest Airlines flew 2,537 at 78.4% on time.
SkyWest Airlines is the most reliable of the six carriers covered here at 78.4% on time across 2,537 flights.
Key figures
On time
71.8%
Arrivals under 15 minutes late, of 16,014 completed departures
Avg delay
57 min
Across delayed arrivals only, not all flights
Cancelled
0.76%
Nationally in July: 2.62%
Whole year
79.5%
SEA across all twelve months
These figures cover 16,214 departures from Seattle-Tacoma International in July 2026. 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
July next to SEA's other months
Against SEA's own year, July ran 8 points worse than the twelve-month rate of 79.5%, which makes it the worst of the twelve months in the data. Either side of it, June ran 78.1% on time and August 72.6%, so a trip moved by a few weeks would have landed in a better stretch.
| Month | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| September 2025 | 14,552 | 82.9% | 50 min | 0.29% | B+ |
| October 2025 | 13,859 | 82.9% | 58 min | 1.16% | B |
| November 2025 | 12,616 | 81.9% | 58 min | 1.69% | B |
| December 2025 | 13,023 | 74.0% | 59 min | 1.02% | C |
| January 2026 | 11,927 | 81.6% | 60 min | 1.91% | B |
| February 2026 | 11,000 | 84.4% | 56 min | 0.78% | B+ |
| March 2026 | 12,830 | 80.2% | 64 min | 2.23% | B |
| April 2026 | 12,864 | 85.6% | 56 min | 0.17% | A+ |
| May 2026 | 14,564 | 82.2% | 52 min | 0.41% | B+ |
| June 2026 | 15,402 | 78.1% | 57 min | 0.48% | B+ |
| July 2026 (this page) | 16,214 | 71.8% | 57 min | 0.76% | C+ |
| August 2026 | 15,908 | 72.6% | 55 min | 0.65% | C+ |
Departure window
The best time of day to leave SEA in July
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 22 points, against 19 points between the best and worst carrier.
- 5am–8am2,050 flights85.7%
- 8am–11am3,234 flights75.7%
- 11am–2pm3,043 flights69.1%
- 2pm–5pm2,364 flights64.0%
- 5pm–8pm2,302 flights66.1%
- 8pm–5am3,221 flights71.5%
Scale runs 55% to 90%.
Book the early departure. Flights leaving between 5am–8am arrive on time 85.7% of the time, against 64.0% for the afternoon window. That is 22 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 3,234 flights scheduled in it.
Across the week, Saturday is the strongest day at 79.4% on time and Thursday the weakest at 61.2%, a spread of 18 points.
Carrier by carrier
Which airlines ran best at SEA in July
The choice of carrier is not cosmetic here. SkyWest Airlines arrives on time 78.4% of the time; Southwest Airlines manages 59.1%. Sample sizes sit next to every figure, because a two-point gap across 981 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Alaska Airlines | 7,592 | 70.1% | 47 min | 0.49% | C+ |
| Delta Air Lines | 3,037 | 74.6% | 60 min | 1.32% | C |
| SkyWest Airlines | 2,537 | 78.4% | 59 min | 0.43% | B+ |
| Southwest Airlines | 981 | 59.1% | 52 min | 0.31% | D+ |
| United Airlines | 978 | 70.9% | 80 min | 1.23% | C |
| American Airlines | 721 | 74.9% | 112 min | 1.11% | C |
| Frontier Airlinesthin sample | 155 | 77.6% | 52 min | 1.94% | B |
| Envoy Airthin sample | 120 | 76.5% | 75 min | 0.00% | B+ |
| JetBlue Airwaysthin sample | 93 | 41.0% | 146 min | 10.75% | F− |
The spread between SkyWest and Southwest is 19 points, wide enough that it should decide the booking. On a hundred trips that is 19 more arrivals inside the on-time window.
Route by route
Busiest routes out of SEA in July
| Route | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| SEA to ANC · Anchorage | 721 | 75.2% | 48 min | 0.28% | B+ |
| SEA to DEN · Denver | 678 | 68.2% | 56 min | 0.15% | C+ |
| SEA to LAX · Los Angeles | 668 | 70.2% | 64 min | 0.45% | C+ |
| SEA to SFO · San Francisco | 666 | 35.0% | 57 min | 0.90% | F+ |
| SEA to ORD · Chicago | 608 | 70.6% | 96 min | 1.48% | C |
| SEA to PHX · Phoenix | 578 | 67.1% | 58 min | 0.52% | C+ |
| SEA to DFW · Dallas-Fort Worth | 501 | 71.1% | 82 min | 0.00% | C+ |
| SEA to LAS · Las Vegas | 492 | 73.6% | 51 min | 0.81% | C+ |
| SEA to SAN · San Diego | 457 | 64.7% | 45 min | 0.44% | D+ |
| SEA to SJC · San Jose | 438 | 69.9% | 48 min | 0.00% | C+ |
| SEA to SMF · Sacramento | 429 | 74.3% | 50 min | 0.23% | C+ |
| SEA to PDX · Portland | 426 | 76.7% | 42 min | 0.23% | B+ |
| SEA to SLC · Salt Lake City | 411 | 76.6% | 55 min | 0.24% | B+ |
| SEA to GEG · Spokane | 385 | 73.4% | 60 min | 0.52% | C+ |
| SEA to SNA · Santa Ana | 369 | 74.7% | 48 min | 0.27% | C+ |
| SEA to ATL · Atlantathin sample | 348 | 76.0% | 55 min | 0.57% | B+ |
| SEA to BOS · Bostonthin sample | 317 | 66.1% | 79 min | 2.84% | C |
| SEA to BOI · Boisethin sample | 303 | 78.8% | 60 min | 0.00% | B+ |
| SEA to MSP · Minneapolisthin sample | 290 | 83.4% | 60 min | 0.00% | B+ |
| SEA to JFK · New Yorkthin sample | 279 | 71.6% | 89 min | 8.24% | C− |
| SEA to ONT · Ontariothin sample | 256 | 67.9% | 46 min | 1.56% | C |
| SEA to EWR · Newarkthin sample | 246 | 75.1% | 80 min | 4.88% | B− |
| SEA to HNL · Honoluluthin sample | 243 | 54.0% | 56 min | 1.65% | F |
| SEA to IAH · Houstonthin sample | 231 | 81.7% | 85 min | 0.43% | B+ |
| SEA to FAI · Fairbanksthin sample | 217 | 70.6% | 52 min | 0.46% | C+ |
Delay causes
What held SEA up in July
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 257,000 reported delay minutes.
- 41%Carrier
- 28%Late-arriving aircraft
- 26%National Airspace System
- 5%Extreme weather
- 0%Security
The largest share of delay minutes, 41%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 104,000 of the 257,000 delay minutes reported here. The split is drawn from 257,164 reported delay minutes.
Cancellations are rare at 0.76%, below the national 2.62% 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.
7.3% of arrivals land an hour or more late, close to the national 11.3%, 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 an hour, which a normal layover absorbs.
What to do with this
Flying from SEA in July
For a July trip through SEA: plan on this being one of the airport's harder months. The 5am–8am departures held up best at 85.7% on time, and with 7.3% of arrivals an hour or more late, a connection here deserves more slack than the same trip in April would.
Related
Where to go next
- Seattle-Tacoma International (SEA), the whole year
- SEA in September82.9%
- SEA in October82.9%
- SEA in November81.9%
- SEA in December74.0%
- SEA in January81.6%
- SEA in February84.4%
- SEA in March80.2%
- SEA in April85.6%
- SEA in May82.2%
- SEA in June78.1%
- SEA in August72.6%
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.