From the Dictionary of Rain Words and Expressions

The average annual precipitation on Earth is about 1,000 mm, while Japan's is approximately 1,800 mm, significantly higher than the world average. This difference is due to Japan being surrounded by the sea and having a concentration of “water highways” in the sky that bring rain throughout the seasons from typhoons, the rainy season front, the autumn rain front, and snow clouds, as noted in the Dictionary of Rain Words. This dictionary features about 1,190 words related to rain in modern Japanese. We will introduce some particularly beautiful rain words and phrases from this collection.

Expressions for Spring Rain

春時雨Harushigure: A sudden spring rain that falls in the spring. Also referred to as Haru no shigure 春の時雨.

桜流しSakura nagashi: Rain that falls on cherry blossoms, causing them to scatter. This term comes from the Kimotsuki region of Kagoshima Prefecture. "Nagashi" refers to rain that continues for several days or the rainy season.

緑雨Ryokū: Rain that falls on fresh green, typically in May. After the rain, young leaves are blown by the wind, glistening with raindrops. The "green" in Ryokū refers to the color of tree leaves, and this rain is also known as "young leaf rain" (若葉雨), "jade rain" (翠雨), or "blue* rain" (青雨) *Traditionally in Japan, the word Ao=青=blue is used to describe young leaves.

Expressions for Summer Rain

涼雨Ryōu: A pleasant, cooling rain in late summer that brings a sense of refreshment, or sometimes, a quiet melancholy. In the intense heat of summer, even the smallest hint of coolness is welcomed, making rain especially cherished. "Ryōu" carries a subtle sense that autumn is beginning to approach, even though it is still summer.

錦雨 Kin'u: A summer rain that arrives as a blessing after a long dry spell. The term "kin" (錦), meaning "brocade," reflects the sense of admiration and gratitude for this precious rain, akin to treasures such as gold, silver, coral, silk, and brocade.

Rain Expressions That Leave a Lasting Impression

狐雨 Kitsune-ame: A light rain falling from a sunny sky, also known as a "sun shower" or  “fox's wedding." This term likely originates from folklore, as foxes are believed to be tricksters, creating a mysterious or playful atmosphere when rain falls despite clear skies.

銀竹Ginchiku: Rain that shines and sparkles as it falls under beams of light. The strong rain streaks catch light breaking through the clouds, resembling silver bamboo. This term is also used to describe a heavy downpour.

星屑の雨 Hoshikuzu no ame: Rain formed from cosmic dust that serves as nuclei for raindrops. According to "Ame nochi Hare," compiled by the Asahi Newspaper's social department, Dr. Bowen, an Australian meteorologist, discovered that about 30 days after a meteor shower, rainfall tends to increase due to cosmic dust falling into the atmosphere. The notion of stardust in the rain evokes a sense of dreaminess and joy.

After reading "The Dictionary of Rain Words," I quoted memorable words with their meanings, capturing the essence of Japan's unique expressions of rain. Many words related to rain in Japan pertain to spring, likely because the rainy season occurs during this time. The abundance of rain-related terms that incorporate Japan's representative spring flowers, such as plum and cherry blossoms, is for the same reason. In contrast, winter often brings snow, resulting in fewer words related to winter rain. Additionally, numerous region-specific rain-related terms exist, which likely increase as they reflect the unique weather conditions of each area.

This was an introduction to rain-related words in Japan. Thank you for taking the time to read through it.

Reference
Kurashima, Atsushi, and Harada, Minoru. Ame no Kotoba Jiten [Dictionary of Rain Words]. Kodansha Ltd., 2014.