As of Jun 19, 2026, 8:24 PM, peak season now, through ~June 25. Earth Exhibit tracks the live conditions and flags it the moment it is on.
In the cool, misty mountain forests of central and northern Japan, the woodland perennial Diphylleia grayi (sankayō) blooms in late spring and early summer.
Its small white petals are loosely structured, and when soaked by rain or mountain mist the air gaps between the petal cells fill with water — so light passes straight through instead of scattering, and the flowers turn nearly transparent, like petals of glass.
As they dry, air returns and they fade back to opaque white.
The reversible transformation, paired with Japan's early-summer rainy season, makes a rain-soaked hike to a sankayō slope one of the most quietly magical blooms in the country.
Where to see it
A taste of where to see it. The full map, exact coordinates and the best timing for each spot live in the app.
| Viewing spots |
|---|
| Tamoyachi Wetland, Hakkōda Mountains |
| Tsugaike Nature Park (Tsugaike Shizen-en) |
| + 1 more spot, with exact coordinates and timing, in the app → |
This is the short version
This page shows a taste. The app has the full list of where to see this, the exact timing, and live conditions for 1,000+ natural phenomena worldwide, so you know the moment one is genuinely worth the trip.