IOP + West Wind = 16.4m! Wind Direction Analysis (3,200 Observations)
2026-03-16
IOP's visibility swings up to 4.3m depending on wind direction. West wind days average 16.4m vs south wind at 12.1m — the same site feels like a different ocean. We analyzed 3,252 observations matched with weather data across 8 compass directions.
Visibility by 8 Wind Directions
W–NW winds bring 16m+ while S–SE winds drop to 12m. The 4.3m gap is significant in perceived clarity (15m+ feels 'clear', 12m feels 'average').
Why West–NW Wind Boosts Visibility
Offshore Wind Pushes Coastal Water Out
IOP faces the Pacific on East Izu. West–NW wind blows offshore, pushing plankton-rich coastal water out. Clear deep water rises to replace it (Ekman transport). Winter high-pressure patterns that bring NW winds create IOP's best conditions. (JMA Tokai Sea Conditions)
South Wind Is Onshore — Brings Turbidity
South wind blows onshore, pushing surface water — rich in plankton — toward shore. Summer south winds carry warm, humid air along with turbid surface water. Southwest wind (12.3m) shows the same pattern.
Practical: Maximizing IOP Visibility
- Check forecast for W–NW wind days (winter high-pressure pattern)
- Winter (Dec–Feb) × NW wind = golden conditions, 18m+ possible
- South wind forecast? Consider West Izu (Koganezaki, Kumomi) instead
- NE wind (14.0m) has 988 obs — memorize as IOP's 'normal day' baseline
About the Data
3,252 IOP observations matched with Open-Meteo wind direction. Classified into 8 compass directions (45° each). NE wind dominates with 988 obs (Izu's prevailing wind).
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