1.
autumn leaf viewing; maple leaf viewing
The activity of going out to view autumn foliage, especially maple leaves.
紅葉狩り is a traditional autumn activity — going to parks, mountains, or temples to enjoy the colorful fall foliage. It is the autumn counterpart of 花見 (cherry blossom viewing) in spring.
Etymology
紅葉 (autumn leaves) + 狩り (hunting). 狩り originally meant "hunting" but evolved to mean "going out to enjoy" nature. The same pattern appears in いちご狩り (strawberry picking).
Cultural note
Roughly October to early December: the colours peak first in Hokkaido and the mountains and move south and down into the lowlands; Kyoto peaks in late November.
CULTURAL NOTE (famous spots):
京都, 日光, and 箱根 are among the most popular 紅葉狩り destinations.