From October to March, Ozu City is frequently blanketed by mystical sea-like mists,

creating breathtakingly beautiful and otherworldly scenes.

Take the opportunity to immerse yourself

in the natural wonders brought by Ozu’s mist.

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Ozu Castle Town Enveloped by the Sea of Clouds

Due to the unique topography of Ozu City, the chances of seeing a sea of clouds are exceptionally high.
Look out for these conditions to catch the best views:
・Large temperature differences between day and night
・High humidity during the night
・Calm, windless weather

Sea of Clouds from Mt. Tomisu

From November through March, early morning mists shroud Ozu, wrapping the castle town in a white veil.
This “sea of clouds” phenomenon offers an ethereal and magical experience.
You can easily enjoy this mystical phenomenon at Ozu’s Mt. Tomisu.

Ozu’s Mt. Tomisu stands at approximately 320 meters at the heart of the Ozu Basin.
Early mornings, especially after sunrise, the area around the mountain is often engulfed in mist. 
However, the timing depends on the day’s weather. On clear days, between 8:00 AM and 11:00 AM, the mist clears at the peak, unveiling the town below shrouded in a sea of clouds. If the weather forecast predicts clear skies and you find Ozu enveloped in mist, it’s the perfect chance to witness the sea of clouds.
Waiting atop Mt. Tomisu as the mist gradually dissipates provides an unforgettable view.

Ozu City also provides a Mt. Tomisu Live Camera, offering a real-time view of the scenery from the observation deck. 
Check the camera feed from town before heading out to ensure optimal viewing conditions.

While less accessible than Mt. Tomisu, the Sea of Clouds Observation Deck offers a higher vantage point for viewing.
At dawn, you can witness a mesmerizing view of the clouds flowing from Ozu's Niiya district toward the city center.
However, please note that the road leading to the observatory is extremely narrow, so caution is essential when visiting.
For the latest information on the Sea of Clouds Observation Deck, be sure to check the Yanagisawa Community Center blog as a helpful resource.

Hiji River Arashi Flowing into the Seto Inland Sea

Ozu’s unique landscape also brings another natural wonder: the Hiji River Arashi, 
an awe-inspiring phenomenon exclusive to Ozu’s Nagahama area.
On clear mornings, mist from the Ozu Basin and steaming fog rising from the Hiji River are carried by strong winds into the Seto Inland Sea. 
Occurring roughly a dozen times a year, this mesmerizing sight draws visitors nationwide.
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Local Forecasts for the Hiji River Arashi

Though the Hiji River Arashi requires specific conditions to form, local efforts have made it possible to predict its occurrence.
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The Hiji River Arashi Forecast Association, formed by local volunteers, provides daily predictions during the season on their YouTube channel.
Their forecasts rely on local knowledge, weather charts, and meteorological data, offering invaluable insight for those planning a visit.
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AI Predictions for the Hiji River Arashi

A new AI-powered prediction system, developed through collaboration between Okayama University of Science’s Ohashi Laboratory (Faculty of Biosphere-Geosphere Science) and Tottori University of Environmental Studies’ Shigeta Laboratory, calculates the probability of Hiji River Arashi occurrences. Predictions are made available online, providing an additional resource for visitors.
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Where to Witness the Hiji River Arashi

The Hiji River Arashi is best viewed in Nagahama, Ozu City.
Recommended viewing spots include:
Hiji River Arashi Observation Park - for a bird’s-eye view.
Nagahama Bridge - to experience the phenomenon up close.
The versatility of viewing experiences is one of the Hiji River Arashi’s many charms.