Weather in Tokyo in September

How September compares

September is the 3rd warmest month of the year in Tokyo and ranks 78th of 134 destinations we compare for September - see where else is hot in September. Against London's average high of 18.6°C in September, Tokyo is 7.4°C warmer by day and 8.8°C warmer at night.

Daytime and night-time in September

The typical September day in Tokyo peaks at 26.0°C, but that is an average: the warmest 10% of days reach 29.9°C or more. About 64% of days top 25°C and 1 in 10 pass 30°C. Nights average 20.0°C; one night in ten drops to 15.9°C or lower, so pack a layer for evenings. Between 1991 and 2020 the hottest September day here reached 35.5°C (2019-09-09) and the coldest night 10.8°C (2001-09-24).

Rain in September

Wet (more than 8 rainy days): about 14 days with 1 mm or more, 185 mm in total. Year to year it varies a lot - the wettest September was 2018 with 356 mm, the driest 1999 with 42 mm. Humidity averages 81%.

Sea temperature in September

The sea averages 25.1°C - warm enough to swim (22°c+). Depending on the year it ranges from 24.0°C to 26.1°C. For the warmest sea here, come in August (26.7°C).

Sunshine and daylight

Around 4.0 hours of sunshine a day (estimated from cloud cover), 12.2 hours of daylight: the sun rises about 05:24 and sets about 17:49 local time in mid-September. Average cloud cover is 67%.

Is September a good time to visit Tokyo?

It is a reasonable choice: hot days but expect showers. The best months for Tokyo on our scoring are August, September, July; months averaging 25°C or more: Jul, Aug, Sep.

Warm enough for summer clothes, with sticky spells

September is still a hot month in Tokyo, so pack mainly light, breathable clothes rather than a typical UK autumn wardrobe. Humidity averages 81%, which can make walking feel more tiring than the temperature alone suggests. Days reach 30°C on 10% of occasions, so leave room for breaks indoors when the heat builds and avoid making your most demanding walks a midday commitment. Evenings are generally warm enough that a heavy jacket is unnecessary, although a light layer is sensible: the coldest 10% of nights fall to 16°C or below. This suits travellers comfortable with warmth, but is less appealing if you prefer cool conditions for exploring on foot.

Treat rain as part of the trip

With about 14 rainy days, wet weather deserves a place in your plans rather than being treated as an unlikely interruption. That does not mean every affected day is a washout, but it does make a rigid schedule of outdoor activities a poor fit. Carry a compact umbrella and choose footwear you can comfortably wear in the wet. A light waterproof is useful, though heavy rainwear may feel uncomfortable in the humidity. Keep indoor options available and move outdoor time around the forecast. September is a reasonable compromise if warmth matters more to you than dependable sunshine; it is less convincing if rain would spoil the main purpose of your holiday.