Winter day (fuyubi)

Definition: the temperature that makes a winter day

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

Winter days in Tokyo

Days per year (1996–2025)

Number of winter 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: 1881 (98 days), 1876 (86 days), 1884 (83 days) (records 1875–2025; days with observations only).

More about the winter day

A winter day is a day on which the daily minimum 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). Only that day's minimum temperature counts; how warm it got during the day does not matter.

Besides winter days, the terms that distinguish degrees of cold include midwinter days (daily maximum temperature below 0°C). Both use 0°C as the line, but winter days look at the minimum temperature and midwinter days at the maximum, and the two show stages in the depth of cold. A day that drops below 0°C only in the morning and warms up during the day is a winter day, and a day that never reaches 0°C all day is a midwinter day. A day that counts as a midwinter day is also a winter day, because its minimum temperature is below 0°C too.

The 0°C line marks the boundary of whether water freezes. On the morning of a winter day, puddles and water on roads freeze, water left outside freezes, and frost forms on car windows. Air temperature is measured for air at a height above the ground, so places close to the ground can get colder than that, and frost can form even when the air temperature is slightly above 0°C.

When the number of winter days in Tokyo is listed year by year, earlier years in the record rank among the highest of all time. This page shows that change and this year's situation across Japan. Comparing it with the page on midwinter days shows the difference in the depth of cold, and if there is an area you are curious about, you can trace its records from each station's page.