In winter, the days are short and the nights are long. In summer, the days are long and the nights are short. In between, there is a day where the day and night are equal in length. This is called the spring equinox. This year’s equinox is today! (But it’s tomorrow on the Japanese calendar.)
冬は昼が短くて夜が長い、夏は昼が長くて夜が短いですね。その間に昼と夜の長さが同じ日があります。これは春分の日で今年は今日です！（日本のカレンダーでは明日ですけどね。）
