Other forms: rainier; rainiest; rainily
Rainy things are affected by rain in some way, like rainy weather or a rainy afternoon.
You can describe certain places as rainy, like Mt. Waialeale on the Hawaiian island of Kauai, or Mawsynram in India, both of which are often cited as being the most rainy place on earth. The phrase "a rainy day" uses rainy figuratively, to represent possible future bad luck or hard times: "You should always save some of your salary in case of a rainy day."