Yokosuka marine weather forecast
Yokosuka (JPYOS) is a port in Japan at 35°17.0′N 139°40.0′E. Today (Sep 17): NNE wind 24–31 kn, waves 2.7–3.3 m, from the ECMWF IFS run 2026-09-17 00z. The live chart on this page shows current conditions and plans weather-optimized departures from this harbor.
Port facts (NGA World Port Index)| Position | 35°17.0′N 139°40.0′E |
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| UN/LOCODE | JPYOS |
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| Harbor size | Medium |
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| Harbor type | Coastal natural harbor |
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| Shelter | Good |
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| Channel depth | 14 m |
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| Anchorage depth | 23 m |
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| Tide range | 2 m |
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| Pilotage | Compulsory |
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| Time zone | Asia/Tokyo |
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Facilities & services (NGA World Port Index)| Tugs | Assistance available |
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| Supplies | Fuel oil, diesel, water, provisions |
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| Repairs | Limited |
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| Medical facilities | Available |
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| Largest vessel | 10 m draft |
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10-day marine forecast — Yokosuka
| Date | Wind | Gusts | Waves |
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| NNE 24–31 kn | 42 kn | 2.7–3.3 m |
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| NNE 27–30 kn | 43 kn | 3.2–3.4 m |
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| NNE 22–27 kn | 36 kn | 3.5–3.6 m |
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| NNE 31–46 kn | 77 kn | 4.3–6.8 m |
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| NE 4–20 kn | 25 kn | 2.1–4.0 m |
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| ENE 18–19 kn | 24 kn | 1.8–1.9 m |
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| ENE 13–13 kn | 16 kn | 1.4–1.4 m |
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| N 2–2 kn | 12 kn | 0.9–0.9 m |
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| ENE 15–15 kn | 21 kn | 1.4–1.4 m |
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| SE 10–10 kn | 13 kn | 1.0–1.0 m |
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Forecast from the ECMWF IFS model run , waves from ECMWF WAM. Updated with each model cycle; the live chart below recalculates for your departure time and vessel.
What to watch in the forecast
Across the loaded 10-day outlook, the strongest daily modeled wind reaches 46 kn on Sep 20. The highest modeled significant wave height is 6.8 m on Sep 20. Compare the dated model run with official forecasts and warnings before departure.
Frequently asked
How is the weather at Yokosuka right now?
As of the ECMWF IFS run 2026-09-17 00z: NNE wind 24–31 kn, waves 2.7–3.3 m. The 10-day outlook is in the forecast table on this page and updates with each model cycle.
How big is the harbor at Yokosuka?
Yokosuka is classed as a medium harbor (coastal natural harbor), with good shelter in the NGA World Port Index.
How deep is the approach to Yokosuka?
Per the NGA World Port Index, the entrance channel carries about 14 m and anchorage depths run about 23 m. Verify against current official charts before entry.
What is the largest vessel Yokosuka can take?
The NGA World Port Index lists the maximum vessel at about 10 m draft. Confirm current limits with the port authority before arrival.