From around October to March, during the early mornings of clear days, a mystical phenomenon known as the "Sea of Clouds" occurs. While several conditions must align for it to form, it is most frequently observed in Ozu between November and December.

The Sea of Clouds in Ozu is particularly striking, with waves of mist rolling over the mountain peaks that surround the basin, creating an otherworldly scene.

Sea of Clouds Observatory

Sea of Clouds Observatory is an observatory located in the Fujinawa district of Ozu City. From about October to March, there is a good chance that you will see Sea of Clouds in the early morning on a sunny day.
The road is narrow, so you need to be careful when driving

Mt.Tomisu

"Mt.Tomisu" is a mountain with an altitude of about 320 m that rises in the center of the Ozu basin. On days when fog occurs in Ozu, depending on the conditions, you can see Sea of Clouds just before the fog disappears between 8:00~11:00. Even if it's pure white when you visit, you can see Sea of Clouds if you wait for the fog to clear. The Mt.Tomisu Observatory at the top of the mountain is about a 10-minute drive from the city.

 

Conditions under which Sea of Clouds occurs

• There is a large difference in temperature between daytime and morning and evening
• High humidity at midnight
• Windless, mild weather
• From sunrise to about 9 a.m.* Sea of Clouds can be seen until March, but November and December are the most common.