Meanings
Noun
day on which the temperature rises above 30°C
Example sentences
明日は真夏日になりそうだって。
It looks like tomorrow will be a very hot summer day.
真夏日には屋内にひっこんで太陽を避けるしか手がないよ。
All I want to do during the dog days is stay indoors and keep out of the sun.