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Maritime shipping

Northwest Seaport Alliance — Monthly Container Volume

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.

Data status: Current
Official statisticCK forecastSource figures as of October 19, 2026 · Exponential smoothing, damped trend, 6 months, 80% range of backtest errorsSources & methods
Sources
The Northwest Seaport Alliance
Period covered
Jan 2015 – Sep 2026
Source figures as of
October 19, 2026
Geography
Ports of Seattle and Tacoma, WA
Sector
Transportation, Maritime Trade & Logistics · Maritime shipping
Seasonal adjustment
Not seasonally adjusted
Transformations
Views other than the level (changes, averages, volatility) are calculated by CK Economics from these figures
Forecast method
Exponential smoothing, damped trend
Assumptions
Past patterns continue, with no policy change or shock; fitted to Jan 2015 – Sep 2026
Horizon
6 months
Interval
80% range of backtest errors
Backtest
Errors 32% smaller than a no-change forecast over the next 3 months, 16% smaller 3–6 months ahead (27 past dates)
Estimated
October 19, 2026
Revisions
Replaced with the source’s latest figures whenever it revises them.
Data status
Current
Limitations
Seasonal swings are left in: compare a period with the same period a year earlier.

Full method · Research standards

Key figures

CK estimateTEUs · calculated by CK Economics from The Northwest Seaport Alliance data

Latest · Sep 2026
265,692
−8.1% vs a year earlier1
12 months to Sep 2026
2,899,614
−12.1% vs prior 12 months2
5-year change
−21.3%
since Sep 2021, −4.7% a year3
10-year change
−20.8%
since Sep 2016, −2.3% a year3
Record high
373,845
Sep 20184
Record low
207,725
Feb 20264
Where the latest ranks
31st pct.
Higher than 31% of the other 140 observations since Jan 20155
CK forecast · Mar 2027
245,000
80% range 199,000–290,0006
  1. 1Latest observation against the observation one year earlier (for weekly data, the nearest within three days).
  2. 2Sum of the latest 12 consecutive months against the sum of the 12 months before them.
  3. 3Latest observation against the observation five and ten years earlier; the yearly rate is the compound annual growth rate over the span.
  4. 4Highest and lowest published observations across the full history shown.
  5. 5Share of the other published observations that are lower than the latest one, rounded down.
  6. 6Final period of the CK forecast, a statistical projection from the model in the methodology, with its 80% range; rounded to three significant figures.

Seasonal pattern

CK estimate

Each month of 2026 and 2025 against the average and range of the same month in 2021–2025. Calculated by CK Economics from the published series.

Monthly TEUs in 2026 and 2025 compared with the 2021–2025 average and range
2026 2025 2021–2025 average 2021–2025 range

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. The 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. All 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. Projection: 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.

How we collect, check and project every dataset →

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.

The 6 projected periods are a CK forecast, not figures from the source; the methodology above describes how they are made.

All data

141 observations, newest first · TEUs

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PeriodValueChange y/y
Sep 2026265,692−8.1%
Aug 2026235,795−8.2%
Jul 2026239,220−4.2%
Jun 2026262,546−4.4%
May 2026238,021−5.1%
Apr 2026218,239−21.4%
Mar 2026278,829−10.1%
Feb 2026207,725−19.4%
Jan 2026228,166−13.9%
Dec 2025237,922−21.9%
Nov 2025253,532−12.6%
Oct 2025233,927−14.4%
Sep 2025289,120−13.6%
Aug 2025256,735−18.7%
Jul 2025249,578−6.0%
Jun 2025274,537−14.7%
May 2025250,851−9.4%
Apr 2025277,828+7.4%
Mar 2025309,993+18.5%
Feb 2025257,705+13.7%
Jan 2025264,869+25.4%
Dec 2024304,748+15.8%
Nov 2024290,210+25.7%
Oct 2024273,355−0.5%

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