Weather in Tokyo in January

A hard month. January is a hard month in Tokyo, and worth planning around. Highs sit at 9 °C and the day is short; this is an indoors-with-excursions month, not an outdoors-all-day one.

January ranks 12 of 12 — near the bottom of Tokyo's year. May is the month that works, and the swing between the two is 26 points, which is a different holiday rather than a slightly better one.

Rain falls on only 6 days, so an itinerary with no wet-weather fallback is a reasonable risk. Layers, and a genuinely waterproof outer — at 9 °C the difference between a good day and a miserable one is entirely down to what you are wearing.

What the averages hide

Averages flatten a month, and this one hides a few things: 12 nights fall below freezing. Across the twenty years measured, the hottest January day reached 17.9 °C and the coldest night fell to -3.2 °C, and the wettest single day dropped 68 mm — roughly 85% of the month's rain in one day.

January is moderately variable: 4 mm in the driest year against 174 mm in the wettest, around an average of 80 mm. Roughly two Januarys in three land near that average, and the third does something else entirely.

Wind is light at 9.6 km/h, so the temperature on the page is close to the temperature on your skin, and humidity runs at 75%, which at 9 °C means damp rather than muggy — the kind of cold that gets into a coat and stays there.

How January sits in the year

This is a turning point in the year — December and February sit on opposite sides of it, so the month contains the change rather than following it.

Daylight in January

January sits at the dark end of Tokyo's year — 10 hours of daylight against 14.6 at midsummer, gaining 0.6 hours across the month. Sightseeing days are genuinely shorter, and an itinerary built for summer will not fit.

Sea temperature

The sea sits at about 19.1 °C in January — swimmable, but it takes a moment to commit. The sea peaks at 27.8 °C in August and bottoms out at 18 °C — water lags the air by a month or two, which is why the best swimming often comes after the best weather.

How busy it gets

Off season. The genuine off season: cheapest by a distance, with the caveat that some tours and restaurants close entirely.

Crowd levels are estimated from climate desirability and school-holiday calendars, not from visitor numbers.

January in Tokyo versus nearby

If Tokyo is one option among several, the nearby comparison is worth making. Utsunomiya is close enough to be a coin toss — 2.5 °C cooler, the same number of rain days. Hamamatsu is a better bet in January — within a degree on temperature, the same number of rain days.

So: January is a compromise. May is 26 points better and is what Tokyo is actually like at its best — worth moving the trip for if that is possible, and worth adjusting expectations for if it is not.

Every month in Tokyo

See all twelve months in Tokyo, or where else to go in January.