{"title":"Northwest Seaport Alliance — Monthly Container Volume","slug":"northwest-seaport-alliance-container-volume","url":"https://www.ckeconomics.com/data/northwest-seaport-alliance-container-volume","description":"Total container volume handled by The Northwest Seaport Alliance, the joint cargo operation of the Ports of Seattle and Tacoma, in twenty-foot equivalent units (TEUs) per month. Includes international imports and exports, loaded and empty, and domestic trade with Alaska and Hawaii.","unit":"TEUs","frequency":"Monthly","updated_at":"2026-10-19T22:36:09.80748+00:00","publisher":"Conkling & Kopcik Economics","source":"The Northwest Seaport Alliance, Cargo Statistics: NWSA Historical Cargo Statistics (Excel file): https://www.nwseaportalliance.com/about-us/cargo-statistics — figures as published on 19 October 2026.","provider":"The Northwest Seaport Alliance","source_url":"https://www.nwseaportalliance.com/about-us/cargo-statistics","source_as_of":"2026-10-19","seasonal_adjustment":"not_seasonally_adjusted","geography":"Ports of Seattle and Tacoma, WA","is_flow":true,"source_urls":["https://www.nwseaportalliance.com/about-us/cargo-statistics"],"methodology":"Each value is the alliance's monthly \"Total TEUs\": international imports (full and empty), international exports (full and empty), and domestic containers to and from Alaska and Hawaii. That is the same total-including-empties basis as the Los Angeles, Long Beach and Oakland series. Unlike those ports, the Pacific Northwest total includes a large domestic trade, about 0.74 million TEUs a year or roughly a fifth of the total, mostly to and from Alaska. It covers NWSA-managed terminals in Seattle and Tacoma plus a privately operated domestic container facility, as the alliance's own totals do.\n\nThe figures come from the alliance's historical cargo workbook, which starts in January 2015, the year the alliance was formed. The alliance records some containers as fractional TEUs, so its totals carry decimals. They are rounded here to whole TEUs, as in its press releases. There are no missing months. Every monthly total is checked against the sum of its six parts. The workbook adds small hand adjustments to a few totals: 1–2 TEUs in November 2015 and 2016, and 187 TEUs added to the 2017 annual total but not assigned to a month. As a result, the 2017 months here sum to 3,701,988 TEUs, against the published annual total of 3,702,174.\n\nAll 20 months from January 2025 to August 2026 match the alliance's monthly TEU report (PDF). August 2026 (235,795 TEUs), May 2026 (238,021) and December 2025 (237,922), plus the 2025 annual total (3,156,598), match its monthly press releases. Each month is usually published around the middle of the following month. Past months can be revised when the workbook is re-issued.\n\nProjection: CK Economics statistical projection. The central path comes from exponential smoothing (ETS) on the logarithm of the series with a damped additive trend and a 12-month seasonal pattern, so recent growth is carried forward but fades over time. It runs only as far ahead as backtests support: the model is refitted at past dates, its forecasts are scored against what happened, and it is shown only for horizons where its errors were at least 5% smaller than those of the better of a no-change forecast and repeating the same month a year earlier. The shaded band is the 80% range of those backtest errors. It is a conditional estimate that extrapolates past patterns: it does not model policy, tariffs, recessions or other shocks, and it is not an official forecast of the source agency.","quality":{"status":"current","label":"Current","explanation":"The latest figures we have collected are for Sep 2026. Oct 2026 is not overdue until February 4, 2027, a generous allowance for a monthly series until we have timed this source’s releases.","last_period":"2026-09-01","next_period":"2026-10-01","next_expected_by":"2027-02-04","provisional_from":null,"revisions_last_30_days":0,"last_revised_at":null,"source_checked_at":"2026-10-19T22:36:05.974082+00:00","definitions":"https://www.ckeconomics.com/methodology#data-status"},"projection":{"label":"Statistical projection","disclosure_label":"CK forecast","model":"ets_log","model_name":"Exponential smoothing, damped trend","fitted_from":"2015-01-01","fitted_to":"2026-09-01","estimated_on":"2026-10-19","horizon_months":6,"horizon_years":null,"band_percent":80,"backtest":{"errors":"log","margin":0.05,"method":"rolling-origin-v2","buckets":[{"best":"naive","mase":0.634,"smape":7.08,"months":3,"passes":true,"origins":27,"rel_mae":0.681,"coverage":0.765,"error_hi":0.105668,"error_lo":-0.125605,"mase_naive":0.931,"mase_snaive":1.263,"smape_naive":10.61,"coverage_model":0.58},{"best":"naive","mase":0.985,"smape":10.83,"months":6,"passes":true,"origins":26,"rel_mae":0.836,"coverage":0.744,"error_hi":0.156793,"error_lo":-0.193644,"mase_naive":1.179,"mase_snaive":1.259,"smape_naive":13.21,"coverage_model":0.615},{"best":"seasonal_naive","mase":1.195,"smape":13.23,"months":12,"passes":false,"origins":24,"rel_mae":0.981,"coverage":0.736,"error_hi":0.2236,"error_lo":-0.238606,"mase_naive":1.311,"mase_snaive":1.217,"smape_naive":13.64,"coverage_model":0.59},{"best":"seasonal_naive","mase":1.641,"smape":18.28,"months":24,"passes":false,"origins":20,"rel_mae":1.272,"coverage":0.804,"error_hi":0.267828,"error_lo":-0.291219,"mase_naive":1.657,"mase_snaive":1.29,"smape_naive":14.51,"coverage_model":0.608},{"best":"seasonal_naive","mase":1.446,"smape":15.86,"months":36,"passes":false,"origins":16,"rel_mae":1.3,"coverage":0.583,"error_hi":0.178912,"error_lo":-0.316415,"mase_naive":1.541,"mase_snaive":1.112,"smape_naive":11.94,"coverage_model":0.844},{"best":"seasonal_naive","mase":1.692,"smape":16.81,"months":60,"passes":false,"origins":8,"rel_mae":1.263,"coverage":null,"error_hi":0.157562,"error_lo":-0.309986,"mase_naive":1.721,"mase_snaive":1.339,"smape_naive":13.53,"coverage_model":0.911}],"data_to":"2026-09-01","origins":27,"withheld":null,"benchmark":"best of naive and seasonal naive","last_origin":"2026-06-01","min_origins":8,"first_origin":"2019-12-01","max_coverage":0.92,"min_coverage":0.65,"horizon_months":6}},"projection_withheld":null,"ck_content_license":"https://creativecommons.org/licenses/by/4.0/","license_note":"CC BY 4.0 covers CK Economics' own calculations and projections. Source data remains under its publisher's terms.","terms":"https://www.ckeconomics.com/terms","citation":"Conkling & Kopcik Economics. (2026). Northwest Seaport Alliance — Monthly Container Volume [Data set]. https://www.ckeconomics.com/data/northwest-seaport-alliance-container-volume","fields":{"period":"Start date of the period (YYYY-MM-DD)","value":"Observation or projection, in TEUs","is_forecast":"true for CK Economics projections, false for published observations","lower":"Lower bound of the projection range (projections only)","upper":"Upper bound of the projection range (projections only)"},"points":[{"period":"2015-01-01","value":220843,"is_forecast":false,"lower":null,"upper":null},{"period":"2015-02-01","value":222009,"is_forecast":false,"lower":null,"upper":null},{"period":"2015-03-01","value":356570,"is_forecast":false,"lower":null,"upper":null},{"period":"2015-04-01","value":286131,"is_forecast":false,"lower":null,"upper":null},{"period":"2015-05-01","value":302907,"is_forecast":false,"lower":null,"upper":null},{"period":"2015-06-01","value":337317,"is_forecast":false,"lower":null,"upper":null},{"period":"2015-07-01","value":289043,"is_forecast":false,"lower":null,"upper":null},{"period":"2015-08-01","value":312027,"is_forecast":false,"lower":null,"upper":null},{"period":"2015-09-01","value":344398,"is_forecast":false,"lower":null,"upper":null},{"period":"2015-10-01","value":295154,"is_forecast":false,"lower":null,"upper":null},{"period":"2015-11-01","value":279813,"is_forecast":false,"lower":null,"upper":null},{"period":"2015-12-01","value":283230,"is_forecast":false,"lower":null,"upper":null},{"period":"2016-01-01","value":257312,"is_forecast":false,"lower":null,"upper":null},{"period":"2016-02-01","value":267257,"is_forecast":false,"lower":null,"upper":null},{"period":"2016-03-01","value":292984,"is_forecast":false,"lower":null,"upper":null},{"period":"2016-04-01","value":281396,"is_forecast":false,"lower":null,"upper":null},{"period":"2016-05-01","value":286989,"is_forecast":false,"lower":null,"upper":null},{"period":"2016-06-01","value":327393,"is_forecast":false,"lower":null,"upper":null},{"period":"2016-07-01","value":295859,"is_forecast":false,"lower":null,"upper":null},{"period":"2016-08-01","value":313811,"is_forecast":false,"lower":null,"upper":null},{"period":"2016-09-01","value":335456,"is_forecast":false,"lower":null,"upper":null},{"period":"2016-10-01","value":304702,"is_forecast":false,"lower":null,"upper":null},{"period":"2016-11-01","value":336381,"is_forecast":false,"lower":null,"upper":null},{"period":"2016-12-01","value":316217,"is_forecast":false,"lower":null,"upper":null},{"period":"2017-01-01","value":301132,"is_forecast":false,"lower":null,"upper":null},{"period":"2017-02-01","value":263705,"is_forecast":false,"lower":null,"upper":null},{"period":"2017-03-01","value":334436,"is_forecast":false,"lower":null,"upper":null},{"period":"2017-04-01","value":282731,"is_forecast":false,"lower":null,"upper":null},{"period":"2017-05-01","value":323556,"is_forecast":false,"lower":null,"upper":null},{"period":"2017-06-01","value":323379,"is_forecast":false,"lower":null,"upper":null},{"period":"2017-07-01","value":295968,"is_forecast":false,"lower":null,"upper":null},{"period":"2017-08-01","value":337720,"is_forecast":false,"lower":null,"upper":null},{"period":"2017-09-01","value":323478,"is_forecast":false,"lower":null,"upper":null},{"period":"2017-10-01","value":303951,"is_forecast":false,"lower":null,"upper":null},{"period":"2017-11-01","value":299150,"is_forecast":false,"lower":null,"upper":null},{"period":"2017-12-01","value":312782,"is_forecast":false,"lower":null,"upper":null},{"period":"2018-01-01","value":256212,"is_forecast":false,"lower":null,"upper":null},{"period":"2018-02-01","value":280737,"is_forecast":false,"lower":null,"upper":null},{"period":"2018-03-01","value":302516,"is_forecast":false,"lower":null,"upper":null},{"period":"2018-04-01","value":279715,"is_forecast":false,"lower":null,"upper":null},{"period":"2018-05-01","value":309243,"is_forecast":false,"lower":null,"upper":null},{"period":"2018-06-01","value":351284,"is_forecast":false,"lower":null,"upper":null},{"period":"2018-07-01","value":327462,"is_forecast":false,"lower":null,"upper":null},{"period":"2018-08-01","value":314321,"is_forecast":false,"lower":null,"upper":null},{"period":"2018-09-01","value":373845,"is_forecast":false,"lower":null,"upper":null},{"period":"2018-10-01","value":333995,"is_forecast":false,"lower":null,"upper":null},{"period":"2018-11-01","value":319242,"is_forecast":false,"lower":null,"upper":null},{"period":"2018-12-01","value":349055,"is_forecast":false,"lower":null,"upper":null},{"period":"2019-01-01","value":326228,"is_forecast":false,"lower":null,"upper":null},{"period":"2019-02-01","value":269233,"is_forecast":false,"lower":null,"upper":null},{"period":"2019-03-01","value":336828,"is_forecast":false,"lower":null,"upper":null},{"period":"2019-04-01","value":323948,"is_forecast":false,"lower":null,"upper":null},{"period":"2019-05-01","value":315792,"is_forecast":false,"lower":null,"upper":null},{"period":"2019-06-01","value":343221,"is_forecast":false,"lower":null,"upper":null},{"period":"2019-07-01","value":326515,"is_forecast":false,"lower":null,"upper":null},{"period":"2019-08-01","value":320564,"is_forecast":false,"lower":null,"upper":null},{"period":"2019-09-01","value":347278,"is_forecast":false,"lower":null,"upper":null},{"period":"2019-10-01","value":310066,"is_forecast":false,"lower":null,"upper":null},{"period":"2019-11-01","value":271178,"is_forecast":false,"lower":null,"upper":null},{"period":"2019-12-01","value":284452,"is_forecast":false,"lower":null,"upper":null},{"period":"2020-01-01","value":263816,"is_forecast":false,"lower":null,"upper":null},{"period":"2020-02-01","value":260932,"is_forecast":false,"lower":null,"upper":null},{"period":"2020-03-01","value":264133,"is_forecast":false,"lower":null,"upper":null},{"period":"2020-04-01","value":247675,"is_forecast":false,"lower":null,"upper":null},{"period":"2020-05-01","value":240671,"is_forecast":false,"lower":null,"upper":null},{"period":"2020-06-01","value":287036,"is_forecast":false,"lower":null,"upper":null},{"period":"2020-07-01","value":270388,"is_forecast":false,"lower":null,"upper":null},{"period":"2020-08-01","value":276407,"is_forecast":false,"lower":null,"upper":null},{"period":"2020-09-01","value":308682,"is_forecast":false,"lower":null,"upper":null},{"period":"2020-10-01","value":296892,"is_forecast":false,"lower":null,"upper":null},{"period":"2020-11-01","value":301932,"is_forecast":false,"lower":null,"upper":null},{"period":"2020-12-01","value":301814,"is_forecast":false,"lower":null,"upper":null},{"period":"2021-01-01","value":289187,"is_forecast":false,"lower":null,"upper":null},{"period":"2021-02-01","value":268216,"is_forecast":false,"lower":null,"upper":null},{"period":"2021-03-01","value":339322,"is_forecast":false,"lower":null,"upper":null},{"period":"2021-04-01","value":303642,"is_forecast":false,"lower":null,"upper":null},{"period":"2021-05-01","value":336397,"is_forecast":false,"lower":null,"upper":null},{"period":"2021-06-01","value":344573,"is_forecast":false,"lower":null,"upper":null},{"period":"2021-07-01","value":309722,"is_forecast":false,"lower":null,"upper":null},{"period":"2021-08-01","value":313127,"is_forecast":false,"lower":null,"upper":null},{"period":"2021-09-01","value":337513,"is_forecast":false,"lower":null,"upper":null},{"period":"2021-10-01","value":314801,"is_forecast":false,"lower":null,"upper":null},{"period":"2021-11-01","value":325604,"is_forecast":false,"lower":null,"upper":null},{"period":"2021-12-01","value":254102,"is_forecast":false,"lower":null,"upper":null},{"period":"2022-01-01","value":272281,"is_forecast":false,"lower":null,"upper":null},{"period":"2022-02-01","value":298046,"is_forecast":false,"lower":null,"upper":null},{"period":"2022-03-01","value":330906,"is_forecast":false,"lower":null,"upper":null},{"period":"2022-04-01","value":266635,"is_forecast":false,"lower":null,"upper":null},{"period":"2022-05-01","value":329740,"is_forecast":false,"lower":null,"upper":null},{"period":"2022-06-01","value":309123,"is_forecast":false,"lower":null,"upper":null},{"period":"2022-07-01","value":260572,"is_forecast":false,"lower":null,"upper":null},{"period":"2022-08-01","value":280436,"is_forecast":false,"lower":null,"upper":null},{"period":"2022-09-01","value":285315,"is_forecast":false,"lower":null,"upper":null},{"period":"2022-10-01","value":272129,"is_forecast":false,"lower":null,"upper":null},{"period":"2022-11-01","value":247037,"is_forecast":false,"lower":null,"upper":null},{"period":"2022-12-01","value":231799,"is_forecast":false,"lower":null,"upper":null},{"period":"2023-01-01","value":213095,"is_forecast":false,"lower":null,"upper":null},{"period":"2023-02-01","value":225747,"is_forecast":false,"lower":null,"upper":null},{"period":"2023-03-01","value":240979,"is_forecast":false,"lower":null,"upper":null},{"period":"2023-04-01","value":232321,"is_forecast":false,"lower":null,"upper":null},{"period":"2023-05-01","value":229974,"is_forecast":false,"lower":null,"upper":null},{"period":"2023-06-01","value":254458,"is_forecast":false,"lower":null,"upper":null},{"period":"2023-07-01","value":234875,"is_forecast":false,"lower":null,"upper":null},{"period":"2023-08-01","value":242700,"is_forecast":false,"lower":null,"upper":null},{"period":"2023-09-01","value":331685,"is_forecast":false,"lower":null,"upper":null},{"period":"2023-10-01","value":274626,"is_forecast":false,"lower":null,"upper":null},{"period":"2023-11-01","value":230787,"is_forecast":false,"lower":null,"upper":null},{"period":"2023-12-01","value":263171,"is_forecast":false,"lower":null,"upper":null},{"period":"2024-01-01","value":211283,"is_forecast":false,"lower":null,"upper":null},{"period":"2024-02-01","value":226603,"is_forecast":false,"lower":null,"upper":null},{"period":"2024-03-01","value":261495,"is_forecast":false,"lower":null,"upper":null},{"period":"2024-04-01","value":258677,"is_forecast":false,"lower":null,"upper":null},{"period":"2024-05-01","value":276854,"is_forecast":false,"lower":null,"upper":null},{"period":"2024-06-01","value":321748,"is_forecast":false,"lower":null,"upper":null},{"period":"2024-07-01","value":265504,"is_forecast":false,"lower":null,"upper":null},{"period":"2024-08-01","value":315739,"is_forecast":false,"lower":null,"upper":null},{"period":"2024-09-01","value":334518,"is_forecast":false,"lower":null,"upper":null},{"period":"2024-10-01","value":273355,"is_forecast":false,"lower":null,"upper":null},{"period":"2024-11-01","value":290210,"is_forecast":false,"lower":null,"upper":null},{"period":"2024-12-01","value":304748,"is_forecast":false,"lower":null,"upper":null},{"period":"2025-01-01","value":264869,"is_forecast":false,"lower":null,"upper":null},{"period":"2025-02-01","value":257705,"is_forecast":false,"lower":null,"upper":null},{"period":"2025-03-01","value":309993,"is_forecast":false,"lower":null,"upper":null},{"period":"2025-04-01","value":277828,"is_forecast":false,"lower":null,"upper":null},{"period":"2025-05-01","value":250851,"is_forecast":false,"lower":null,"upper":null},{"period":"2025-06-01","value":274537,"is_forecast":false,"lower":null,"upper":null},{"period":"2025-07-01","value":249578,"is_forecast":false,"lower":null,"upper":null},{"period":"2025-08-01","value":256735,"is_forecast":false,"lower":null,"upper":null},{"period":"2025-09-01","value":289120,"is_forecast":false,"lower":null,"upper":null},{"period":"2025-10-01","value":233927,"is_forecast":false,"lower":null,"upper":null},{"period":"2025-11-01","value":253532,"is_forecast":false,"lower":null,"upper":null},{"period":"2025-12-01","value":237922,"is_forecast":false,"lower":null,"upper":null},{"period":"2026-01-01","value":228166,"is_forecast":false,"lower":null,"upper":null},{"period":"2026-02-01","value":207725,"is_forecast":false,"lower":null,"upper":null},{"period":"2026-03-01","value":278829,"is_forecast":false,"lower":null,"upper":null},{"period":"2026-04-01","value":218239,"is_forecast":false,"lower":null,"upper":null},{"period":"2026-05-01","value":238021,"is_forecast":false,"lower":null,"upper":null},{"period":"2026-06-01","value":262546,"is_forecast":false,"lower":null,"upper":null},{"period":"2026-07-01","value":239220,"is_forecast":false,"lower":null,"upper":null},{"period":"2026-08-01","value":235795,"is_forecast":false,"lower":null,"upper":null},{"period":"2026-09-01","value":265692,"is_forecast":false,"lower":null,"upper":null},{"period":"2026-10-01","value":236851,"is_forecast":true,"lower":208894,"upper":263248},{"period":"2026-11-01","value":231379,"is_forecast":true,"lower":204068,"upper":257167},{"period":"2026-12-01","value":229763,"is_forecast":true,"lower":198098,"upper":259760},{"period":"2027-01-01","value":209858,"is_forecast":true,"lower":176879,"upper":241335},{"period":"2027-02-01","value":205446,"is_forecast":true,"lower":169278,"upper":240321},{"period":"2027-03-01","value":244529,"is_forecast":true,"lower":199477,"upper":290317}]}