Midwinter day (mafuyubi)

Definition: the temperature that makes a midwinter day

JMA forecast terminology defines it as "a day with a daily maximum temperature below 0 degrees" (source: JMA, Terms used in weather forecasts: temperature and humidity, in Japanese, accessed August 17, 2026).

Midwinter days in Tokyo

Days per year (1996–2025)

Number of midwinter days per year, counted from observations in Tokyo (Kitanomaru Park, Chiyoda City). The station moved from Otemachi in December 2014, so the series may not be continuous across the move. Most on record: 1967 (1 day), 1900 (1 day), 1895 (1 day) (records 1875–2025; days with observations only).

More about the midwinter day

A midwinter day is a day on which the daily maximum temperature is below 0°C. The Japan Meteorological Agency (JMA) lists it with this definition among the terms it uses in weather forecasts (as of August 17, 2026). It means that the temperature did not reach 0°C even at the warmest time of that day.

Comparing it with winter days (daily minimum temperature below 0°C) makes the difference clear. A winter day only needs the temperature to drop below 0°C in the morning, but a midwinter day is a day that never reached 0°C or higher from morning to night. It corresponds to situations such as the temperature not rising despite sunshine, or the whole day passing under a blanket of cold air. A midwinter day is therefore always a winter day as well, and it marks a more severe level of cold, one step beyond.

How familiar this term feels varies greatly with where you live. In inland Hokkaido and Tohoku and at high elevations, midwinter days can continue through the winter, making it a handy line for describing the cold. In places like Tokyo, on the other hand, where the temperature rises during the day even in winter, they appear only rarely even across the full history of records. The same term is an everyday word in some regions and a word of the records in others.

This page shows how the number of days in Tokyo that count as midwinter days has changed over time, alongside this year's situation across Japan. Even if such days are rare in Tokyo's records alone, looking across Japan shows that how severe winter cold gets differs from place to place. If there is an area you are curious about, you can trace the temperatures recorded there from each station's page.