Their store directory says they are available in more than 20 countries including some Asian, but no shop in Japan as of today. So. if you see someone wearing the cloths, it should be purchased outside Japan.
When I visited San Francisco in May, I found the shop in Westfield. Its close-fitting shape, three layers zipper and weird Japanese won my heart. Also, San Francisco weather is cold enough to wear the jacket even in summer.
As a matter of fact, it is in the midst of humid and hot season here in Japan. I have no chance to put on this after coming back from SF. I need to wait for November or December… ^^;
I would say “日本の夏こそ、極度乾燥(しなさい)!” means something like “Japanese summer is what should be dried extremely!”
If model wears this… wow.