From late autumn to early winter, the weather begins to get colder by the day, but occasionally, there are warm, balmy days when a moving high-pressure system sets in or when the typical winter weather pattern weakens. Days such as these are called koharu-biyori (literally, “small spring days”). Koharu is another name for October according to the lunar calendar, and corresponds to around November by today’s calendar. Therefore, warms spell during the period from around October to November are called koharu days, or koharu-biyori.
This expression is not necessarily used throughout Japan, however. In Okinawa, temperatures sometimes reach over 25 C and bring summer days even during the October-November autumn season, so days such as these are called konatsu-biyori (literally, “small summer days”).
Interestingly, warm autumn days are also expressed using the word summer in many foreign countries. For example, they are called “Indian summer” in the United States, “old ladies summer” in Germany, “Saint Martin’s summer” in France, and “ladies summer” in Russia. In Europe, it seems summer is a more favored season compared to spring, because spring is short due to the high latitudes of most countries.
The season that brings koharu-biyori corresponds to the height of autumn foliage, and is the perfect season for outings.