Seattle–Tacoma (SEA)
Seattle–Tacoma International Airport handled 5,287,519 passengers in July 2026, down 2.1% on a year earlier, according to the US BTS.
Flights (arrivals + departures) over time
Data Integrity
The most recent periods19 periods
| Period | Flights (arrivals + departures) 2025 | Flights (arrivals + departures) 2026 | Change vs last year |
|---|---|---|---|
| January | 31,778 | 30,948 | ▼ 2.6% |
| February | 28,533 | 28,820 | ▲ 1.0% |
| March | 33,355 | 32,920 | ▼ 1.3% |
| April | 33,958 | 33,951 | 0.0% |
| May | 38,219 | 37,814 | ▼ 1.1% |
| June | 40,055 | 39,532 | ▼ 1.3% |
| July | 42,302 | 41,488 | ▼ 1.9% |
| August | 41,244 | – | – |
| September | 37,564 | – | – |
| October | 35,903 | – | in progress |
| November | 32,419 | – | – |
| December | 33,900 | – | – |
| Year to date (Jan–Jul) | 248,200 | 245,473 | ▼ 1.1% |
Passengers over time
Data Integrity
The most recent periods19 periods
| Period | Passengers 2025 | Passengers 2026 | Change vs last year |
|---|---|---|---|
| January | 3,520,027 | 3,433,753 | ▼ 2.5% |
| February | 3,240,204 | 3,266,086 | ▲ 0.8% |
| March | 3,890,337 | 3,856,367 | ▼ 0.9% |
| April | 3,986,912 | 3,888,970 | ▼ 2.5% |
| May | 4,507,178 | 4,507,971 | 0.0% |
| June | 4,979,449 | 4,962,922 | ▼ 0.3% |
| July | 5,399,354 | 5,287,519 | ▼ 2.1% |
| August | 5,264,779 | – | – |
| September | 4,414,399 | – | – |
| October | 4,158,857 | – | in progress |
| November | 3,628,038 | – | – |
| December | 3,998,040 | – | – |
| Year to date (Jan–Jul) | 29,523,461 | 29,203,588 | ▼ 1.1% |
Tonnes of cargo over time
Data Integrity
The most recent periods19 periods
| Period | Tonnes of cargo 2025 | Tonnes of cargo 2026 | Change vs last year |
|---|---|---|---|
| January | 37,930 | 41,474 | ▲ 9.3% |
| February | 35,228 | 40,180 | ▲ 14.1% |
| March | 39,906 | 43,906 | ▲ 10.0% |
| April | 39,431 | 49,961 | ▲ 26.7% |
| May | 40,656 | 46,545 | ▲ 14.5% |
| June | 43,494 | 52,658 | ▲ 21.1% |
| July | 49,195 | 53,145 | ▲ 8.0% |
| August | 42,580 | – | – |
| September | 39,932 | – | – |
| October | 42,912 | – | in progress |
| November | 41,835 | – | – |
| December | 44,088 | – | – |
| Year to date (Jan–Jul) | 285,841 | 327,868 | ▲ 14.7% |
Seats offered over time
Data Integrity
The most recent periods19 periods
| Period | Seats offered 2025 | Seats offered 2026 | Change vs last year |
|---|---|---|---|
| January | 4,488,728 | 4,444,356 | ▼ 1.0% |
| February | 4,027,243 | 4,116,685 | ▲ 2.2% |
| March | 4,743,286 | 4,687,846 | ▼ 1.2% |
| April | 4,872,181 | 4,878,961 | ▲ 0.1% |
| May | 5,543,085 | 5,524,507 | ▼ 0.3% |
| June | 5,876,438 | 5,845,503 | ▼ 0.5% |
| July | 6,204,948 | 6,130,833 | ▼ 1.2% |
| August | 6,046,437 | – | – |
| September | 5,480,712 | – | – |
| October | 5,204,374 | – | in progress |
| November | 4,660,631 | – | – |
| December | 4,874,221 | – | – |
| Year to date (Jan–Jul) | 35,755,909 | 35,628,691 | ▼ 0.4% |
Domestic / International
July 2026- Domestic 89.5% 37,144
- International 10.5% 4,344
Domestic / International — flights (arrivals + departures)
Domestic
Data Integrity
The most recent periods19 periods
| Period | Flights (arrivals + departures) 2025 | Flights (arrivals + departures) 2026 | Change vs last year |
|---|---|---|---|
| January | 28,364 | 27,388 | ▼ 3.4% |
| February | 25,431 | 25,664 | ▲ 0.9% |
| March | 29,706 | 29,420 | ▼ 1.0% |
| April | 30,151 | 30,339 | ▲ 0.6% |
| May | 34,123 | 33,851 | ▼ 0.8% |
| June | 35,956 | 35,377 | ▼ 1.6% |
| July | 37,625 | 37,144 | ▼ 1.3% |
| August | 36,802 | – | – |
| September | 33,576 | – | – |
| October | 32,004 | – | in progress |
| November | 29,040 | – | – |
| December | 30,293 | – | – |
| Year to date (Jan–Jul) | 221,356 | 219,183 | ▼ 1.0% |
International
Data Integrity
The most recent periods19 periods
| Period | Flights (arrivals + departures) 2025 | Flights (arrivals + departures) 2026 | Change vs last year |
|---|---|---|---|
| January | 3,414 | 3,560 | ▲ 4.3% |
| February | 3,102 | 3,156 | ▲ 1.7% |
| March | 3,649 | 3,500 | ▼ 4.1% |
| April | 3,807 | 3,612 | ▼ 5.1% |
| May | 4,096 | 3,963 | ▼ 3.2% |
| June | 4,099 | 4,155 | ▲ 1.4% |
| July | 4,677 | 4,344 | ▼ 7.1% |
| August | 4,442 | – | – |
| September | 3,988 | – | – |
| October | 3,899 | – | in progress |
| November | 3,379 | – | – |
| December | 3,607 | – | – |
| Year to date (Jan–Jul) | 26,844 | 26,290 | ▼ 2.1% |
Domestic / International — passengers
Domestic
Data Integrity
The most recent periods19 periods
| Period | Passengers 2025 | Passengers 2026 | Change vs last year |
|---|---|---|---|
| January | 3,024,235 | 2,916,192 | ▼ 3.6% |
| February | 2,798,982 | 2,811,592 | ▲ 0.5% |
| March | 3,362,784 | 3,345,727 | ▼ 0.5% |
| April | 3,422,530 | 3,348,909 | ▼ 2.2% |
| May | 3,914,206 | 3,904,722 | ▼ 0.2% |
| June | 4,347,566 | 4,327,966 | ▼ 0.5% |
| July | 4,685,401 | 4,629,481 | ▼ 1.2% |
| August | 4,555,253 | – | – |
| September | 3,819,021 | – | – |
| October | 3,580,940 | – | in progress |
| November | 3,141,258 | – | – |
| December | 3,456,298 | – | – |
| Year to date (Jan–Jul) | 25,555,704 | 25,284,589 | ▼ 1.1% |
International
Data Integrity
The most recent periods19 periods
| Period | Passengers 2025 | Passengers 2026 | Change vs last year |
|---|---|---|---|
| January | 495,792 | 517,561 | ▲ 4.4% |
| February | 441,222 | 454,494 | ▲ 3.0% |
| March | 527,553 | 510,640 | ▼ 3.2% |
| April | 564,382 | 540,061 | ▼ 4.3% |
| May | 592,972 | 603,249 | ▲ 1.7% |
| June | 631,883 | 634,956 | ▲ 0.5% |
| July | 713,953 | 658,038 | ▼ 7.8% |
| August | 709,526 | – | – |
| September | 595,378 | – | – |
| October | 577,917 | – | in progress |
| November | 486,780 | – | – |
| December | 541,742 | – | – |
| Year to date (Jan–Jul) | 3,967,757 | 3,918,999 | ▼ 1.2% |
Domestic / International — tonnes of cargo
Domestic
Data Integrity
The most recent periods19 periods
| Period | Tonnes of cargo 2025 | Tonnes of cargo 2026 | Change vs last year |
|---|---|---|---|
| January | 26,924 | 27,503 | ▲ 2.1% |
| February | 24,366 | 26,847 | ▲ 10.2% |
| March | 26,335 | 29,849 | ▲ 13.3% |
| April | 27,187 | 35,245 | ▲ 29.6% |
| May | 28,232 | 31,595 | ▲ 11.9% |
| June | 28,339 | 32,427 | ▲ 14.4% |
| July | 29,513 | 33,534 | ▲ 13.6% |
| August | 29,040 | – | – |
| September | 27,911 | – | – |
| October | 29,174 | – | in progress |
| November | 27,392 | – | – |
| December | 29,386 | – | – |
| Year to date (Jan–Jul) | 190,895 | 216,999 | ▲ 13.7% |
International
Data Integrity
The most recent periods19 periods
| Period | Tonnes of cargo 2025 | Tonnes of cargo 2026 | Change vs last year |
|---|---|---|---|
| January | 11,006 | 13,971 | ▲ 26.9% |
| February | 10,862 | 13,333 | ▲ 22.7% |
| March | 13,572 | 14,057 | ▲ 3.6% |
| April | 12,244 | 14,716 | ▲ 20.2% |
| May | 12,424 | 14,950 | ▲ 20.3% |
| June | 15,156 | 20,231 | ▲ 33.5% |
| July | 19,682 | 19,611 | ▼ 0.4% |
| August | 13,540 | – | – |
| September | 12,021 | – | – |
| October | 13,738 | – | in progress |
| November | 14,444 | – | – |
| December | 14,701 | – | – |
| Year to date (Jan–Jul) | 94,946 | 110,869 | ▲ 16.8% |
Domestic / International — seats offered
Domestic
Data Integrity
The most recent periods19 periods
| Period | Seats offered 2025 | Seats offered 2026 | Change vs last year |
|---|---|---|---|
| January | 3,871,495 | 3,781,238 | ▼ 2.3% |
| February | 3,460,030 | 3,541,085 | ▲ 2.3% |
| March | 4,076,614 | 4,062,973 | ▼ 0.3% |
| April | 4,156,929 | 4,200,517 | ▲ 1.0% |
| May | 4,782,658 | 4,779,368 | ▼ 0.1% |
| June | 5,106,761 | 5,077,899 | ▼ 0.6% |
| July | 5,356,465 | 5,353,075 | ▼ 0.1% |
| August | 5,228,034 | – | – |
| September | 4,738,430 | – | – |
| October | 4,460,774 | – | in progress |
| November | 4,031,647 | – | – |
| December | 4,203,123 | – | – |
| Year to date (Jan–Jul) | 30,810,952 | 30,796,155 | 0.0% |
International
Data Integrity
The most recent periods19 periods
| Period | Seats offered 2025 | Seats offered 2026 | Change vs last year |
|---|---|---|---|
| January | 617,233 | 663,118 | ▲ 7.4% |
| February | 567,213 | 575,600 | ▲ 1.5% |
| March | 666,672 | 624,873 | ▼ 6.3% |
| April | 715,252 | 678,444 | ▼ 5.1% |
| May | 760,427 | 745,139 | ▼ 2.0% |
| June | 769,677 | 767,604 | ▼ 0.3% |
| July | 848,483 | 777,758 | ▼ 8.3% |
| August | 818,403 | – | – |
| September | 742,282 | – | – |
| October | 743,600 | – | in progress |
| November | 628,984 | – | – |
| December | 671,098 | – | – |
| Year to date (Jan–Jul) | 4,944,957 | 4,832,536 | ▼ 2.3% |
Load factor (computed)
Data Integrity
Passengers ÷ seats offered, both as reported by the US BTS for the same months. Computed by us; the two source series are shown on this page.
The most recent periods19 periods
| Period | Load factor 2025 | Load factor 2026 | Change vs last year |
|---|---|---|---|
| January | 78.4% | 77.3% | ▼ 1.5% |
| February | 80.5% | 79.3% | ▼ 1.4% |
| March | 82.0% | 82.3% | ▲ 0.3% |
| April | 81.8% | 79.7% | ▼ 2.6% |
| May | 81.3% | 81.6% | ▲ 0.4% |
| June | 84.7% | 84.9% | ▲ 0.2% |
| July | 87.0% | 86.2% | ▼ 0.9% |
| August | 87.1% | – | – |
| September | 80.5% | – | – |
| October | 79.9% | – | in progress |
| November | 77.8% | – | – |
| December | 82.0% | – | – |
| Year-to-date average (Jan–Jul) | 82.3% | 81.6% | ▼ 0.8% |
Seasonality · flights (arrivals + departures) by month
| Year | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 2024 | 28,938 | 29,192 | 33,186 | 33,891 | 37,737 | 40,038 | 42,093 | 41,983 | 38,718 | 35,974 | 32,614 | 33,490 |
| 2025 | 31,778 | 28,533 | 33,355 | 33,958 | 38,219 | 40,055 | 42,302 | 41,244 | 37,564 | 35,903 | 32,419 | 33,900 |
| 2026 | 30,948 | 28,820 | 32,920 | 33,951 | 37,814 | 39,532 | 41,488 |
International share 10% of flights (arrivals + departures) in July 2026
Series depth 36 years from 1990
Busiest destinations
Flights recorded between Oct 12, 2024 and Jul 31, 2026, counted from flight records published by the US BTS. Not a current timetable.
Partial coverage: domestic flights only
| Busiest destinations | Flights | Distance (km) |
|---|---|---|
| Los Angeles International Airport SEA–LAX → | 26,796 | 1,537 |
| Phoenix Sky Harbor International Airport SEA–PHX → | 26,407 | 1,782 |
| San Francisco International Airport SEA–SFO → | 24,540 | 1,093 |
| Ted Stevens Anchorage International Airport SEA–ANC → | 24,147 | 2,326 |
| Denver International Airport SEA–DEN → | 22,655 | 1,645 |
| Harry Reid International Airport SEA–LAS → | 21,101 | 1,395 |
| Chicago O'Hare International Airport SEA–ORD → | 19,156 | 2,762 |
| Dallas Fort Worth International Airport SEA–DFW → | 18,975 | 2,668 |
| Spokane International Airport SEA–GEG → | 18,649 | 359 |
| Portland International Airport SEA–PDX → | 17,409 | 208 |
On-time departures by month
Partial coverage: domestic flights only · 151 of 151 periods have data
74.5% of 16,090 timed departures from Seattle–Tacoma International Airport left within 15 minutes of schedule in July 2026, according to the US BTS. Cancelled flights are excluded.
The most recent periods19 periods
| Period | On-time departures 2025 | On-time departures 2026 | Change vs last year |
|---|---|---|---|
| January | 83.6% | 81.0% | ▼ 3.1% |
| February | 79.9% | 84.6% | ▲ 5.9% |
| March | 83.1% | 77.8% | ▼ 6.4% |
| April | 83.9% | 85.2% | ▲ 1.6% |
| May | 81.3% | 81.0% | ▼ 0.4% |
| June | 73.1% | 75.2% | ▲ 2.9% |
| July | 73.1% | 74.5% | ▲ 1.9% |
| August | 76.2% | – | – |
| September | 84.1% | – | – |
| October | 83.0% | – | in progress |
| November | 84.1% | – | – |
| December | 73.7% | – | – |
| Year-to-date average (Jan–Jul) | 79.7% | 79.9% | ▲ 0.2% |
Flight timing & delays
Historical departures, grouped by the scheduled local time at the departure airport. These are recorded outcomes, not a forecast for your flight.
US domestic sectors recorded by BTS
Source: the US BTS · Oct 12, 2024 → Jul 31, 2026
Lowest average delay05:00–06:001.8min · 4,671 recorded · 4,636 measured
Gap to highest-delay hour12.0min05:00 ↔ 20:00
Recorded flights293,430Seattle–Tacoma International Airport
Departure hour
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| Departure hour | On-time departures | Average departure delay | With departure time | Recorded flights |
|---|---|---|---|---|
| 00:00 | 78.3% | 12.2 min | 1,280 | 1,299 |
| 01:00 | Fewer than 200 measured departures | — | 88 | 89 |
| 02:00 | No observations | — | — | — |
| 03:00 | No observations | — | — | — |
| 04:00 | No observations | — | — | — |
| 05:00 | 94.6% | 1.8 min | 4,636 | 4,671 |
| 06:00 | 92.2% | 3.4 min | 9,332 | 9,420 |
| 07:00 | 89.7% | 4.7 min | 23,526 | 23,758 |
| 08:00 | 88.4% | 4.5 min | 21,756 | 21,984 |
| 09:00 | 84.4% | 6.2 min | 21,533 | 21,694 |
| 10:00 | 78.5% | 10.5 min | 17,847 | 17,975 |
| 11:00 | 74.9% | 12.3 min | 26,561 | 26,760 |
| 12:00 | 78.4% | 10.1 min | 13,248 | 13,344 |
| 13:00 | 78.6% | 11.0 min | 16,776 | 16,873 |
| 14:00 | 78.2% | 11.6 min | 10,350 | 10,425 |
| 15:00 | 77.3% | 11.9 min | 20,036 | 20,197 |
| 16:00 | 76.8% | 11.0 min | 9,369 | 9,444 |
| 17:00 | 77.2% | 12.1 min | 20,341 | 20,496 |
| 18:00 | 76.0% | 11.6 min | 12,258 | 12,352 |
| 19:00 | 78.8% | 9.7 min | 17,046 | 17,141 |
| 20:00 | 72.0% | 13.9 min | 9,270 | 9,336 |
| 21:00 | 77.1% | 10.7 min | 14,816 | 14,956 |
| 22:00 | 73.6% | 12.9 min | 9,480 | 9,562 |
| 23:00 | 77.4% | 11.1 min | 11,519 | 11,654 |
Day of week
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| Day of week | On-time departures | Average departure delay | With departure time | Recorded flights |
|---|---|---|---|---|
| Monday | 79.3% | 10.2 min | 43,519 | 43,875 |
| Tuesday | 83.7% | 6.8 min | 40,229 | 40,444 |
| Wednesday | 82.8% | 7.6 min | 40,419 | 40,632 |
| Thursday | 78.3% | 10.7 min | 43,035 | 43,360 |
| Friday | 78.2% | 11.1 min | 43,116 | 43,606 |
| Saturday | 81.5% | 8.8 min | 37,943 | 38,247 |
| Sunday | 77.9% | 11.4 min | 42,807 | 43,266 |
Month of year
Months combine the same calendar month across the years shown; this is a seasonal pattern, not a monthly time series.
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| Month of year | On-time departures | Average departure delay | With departure time | Recorded flights |
|---|---|---|---|---|
| Jan | 82.3% | 8.7 min | 23,472 | 23,809 |
| Feb | 82.3% | 8.3 min | 21,515 | 21,738 |
| Mar | 80.4% | 9.5 min | 25,076 | 25,407 |
| Apr | 84.6% | 6.1 min | 25,535 | 25,580 |
| May | 81.2% | 8.1 min | 29,081 | 29,194 |
| Jun | 74.2% | 13.3 min | 30,925 | 31,097 |
| Jul | 73.8% | 15.0 min | 32,439 | 32,791 |
| Aug | 76.2% | 11.8 min | 15,864 | 15,970 |
| Sep | 84.1% | 6.0 min | 14,510 | 14,552 |
| Oct | 84.3% | 6.6 min | 22,418 | 22,604 |
| Nov | 85.6% | 5.7 min | 24,810 | 25,069 |
| Dec | 77.0% | 12.3 min | 25,423 | 25,619 |
Delay and on-time rates need at least 200 measured departures per bucket. Smaller samples remain visible in the flight-count chart. An empty slot means no observations, not zero flights.
Recorded outcomes
- On time 79.5% 233,270
- Delayed >15 min 19.7% 57,798
- Cancelled 0.8% 2,362
- Missing departure time 0.0% 0
All recorded flights with a known scheduled local time, counted once. Missing actual times are shown separately.
On time means departing no more than 15 minutes after schedule. Cancelled flights and flights missing departure times are excluded from the on-time rate and average delay.
Environment
Air pollutants at the airport (EPA estimate)
Modelled estimate, not a measurement: aircraft below 3,000 ft (landing and take-off), ground support equipment and auxiliary power units, plus any stationary sources the state reported at the airport site. Cruise emissions are not included.In 2023, the US EPA estimated 2,015 tonnes of nitrogen oxides (NOₓ) and 21.5 tonnes of fine particles (PM2.5) from activity at Seattle–Tacoma International Airport, according to the EPA National Emissions Inventory.
| Pollutant | Unit | 2017 | 2020 | 2023 |
|---|---|---|---|---|
| NOₓ (Nitrogen oxides) | tonnes | 1,851 | 696 | 2,015 |
| CO (Carbon monoxide) | tonnes | 3,877 | 1,366 | 2,239 |
| SO₂ (Sulphur dioxide) | tonnes | 246 | 84.0 | 206 |
| VOC (Volatile organic compounds) | tonnes | 591 | 486 | 236 |
| PM2.5 (Fine particles) | tonnes | 44.0 | 11.8 | 21.5 |
| PM10 (Particulate matter) | tonnes | 44.8 | 12.0 | 21.5 |
| Lead | kg | 18.6 | 5.6 | 1.3 |
| CO₂ (Carbon dioxide) | tonnes | 542,332 | 219,098 | — |
The inventory is published every three years. Coverage changes between editions (about 19,300 airport sites in 2017, 6,000 in 2020, 12,700 in 2023), 2020 reflects the pandemic drop in traffic, and EPA updates its aircraft model between editions — so the columns are not a trend (Los Angeles: 3,562 tonnes of NOₓ in 2017, 8,810 in 2023). CO₂ is only reported for some sites in 2017, for all sites in 2020, and not at all in 2023. EPA publishes US customary units; converted here to metric tonnes (× 0.907) and, for lead, kilograms.
US EPA — National Emissions Inventory