Tokyo has four seasons. Winters are dry and cool, spring is lovely, summer is wet followed by hot and humid, autumn starts out wet and finishes with some of the year's best weather.
January ~ Cold and SunnyDaily High: 9.9°C (49.8°F)
Daily Low: 2.5°C (36.5°F)
Precipitation: dry (52.3 mm)
Sunshine Duration: sunny (187.9 hours)
January is both the coldest and sunniest month of the year in Tokyo. It rarely snows in the city. When it does everyone gets excited about it.
February ~ Cold and SunnyDaily High: 10.4°C (50.7°F)
Daily Low: 2.9°C (37.2°F)
Precipitation: dry (56.1 mm)
Sunshine Duration: sunny (167.3 hours)
February is cold and sunny. It's a little warmer and darker than January.
March ~ Signs of SpringDaily High: 13.3°C (55.9°F)
Daily Low: 5.6°C (42°F)
Precipitation: normal (117.5 mm)
Sunshine Duration: sunny (163.1 hours)
In late March everyone starts thinking about sakura season in Tokyo. The sakura often bloom on March 30th or 31th and the city's parks are filled with hanami parties.
April ~ Spring WeatherDaily High: 18.8°C (65.8°F)
Daily Low: 10.7°C (51°F)
Precipitation: normal (124.5 mm)
Sunshine Duration: sunny (175.4 hours)
Early April is hanami season in Tokyo. It's everyone's favorite time of year. The great spring weather continues to the end of the month when golden week begins.
May ~ Spring WeatherDaily High: 22.8°C (73°F)
Daily Low: 15.4°C (59.7°F)
Precipitation: normal (137.8 mm)
Sunshine Duration: sunny (172.5 hours)
Early May is golden week and Tokyo weather (usually) couldn't be finer. The great weather continues all month.
June ~ Rainy SeasonDaily High: 25.5°C (77.9°F)
Daily Low: 19.1°C (66.4°F)
Precipitation: wet (167.7 mm)
Sunshine Duration: dark (123.2 hours)
Tokyo spring is anticlimactic — weather starts to get good in March, peaks in April and May and becomes miserable in June. June is the start of Tokyo's 6 week rainy season.
Rainy season is a bit of a misnomer because it's actually rainier and darker in September - October. Travel in June is generally cheaper than other times of the year (low season).
July ~ Rainy Season and HotDaily High: 29.4°C (84.9°F)
Daily Low: 23.0°C (73.4°F)
Precipitation: wet (153.5 mm)
Sunshine Duration: normal (143.9 hours)
Rainy season continues until around July 20th (depending on the year). The kids get out of school in mid-July and travel starts to get more expensive again. The end of July is hot and humid.
August ~ Hot, Sunny and HumidDaily High: 31.1°C (88°F)
Daily Low: 24.5°C (76.1°F)
Precipitation: wet (168.2 mm)
Sunshine Duration: sunny (175.3 hours)
August is incredibly hot and humid. However, the sun returns and summer matsuri put the city into a festive mood. August has a traditional holiday known as obon. Everyone travels to the countryside to visit their ancestors graves and families. Beaches and countryside attractions are packed. It's one of the most expensive months for travel within Japan.
August gets its fair share of rain. August and September are the peak season for typhoons in Japan. Typhoons pass fairly quickly and leave good weather in their wake. They can be dangerous in southern Japan (e.g. Okinawa) but have usually weakened before hitting Tokyo.
September ~ Warm And RainyDaily High: 27.2°C (81°F)
Daily Low: 21.1°C (70°F)
Precipitation: very wet (209.9 mm)
Sunshine Duration: dark (117.8 hours)
Despite "rainy season" being in June and July — September is the darkest rainiest month of the year in Tokyo.
October ~ RainyDaily High: 21.8°C (71.2°F)
Daily Low: 15.4°C (59.7°F)
Precipitation: very wet (197.8 mm)
Sunshine Duration: dark (133.4 hours)
October is similar to September — rainy and dark. The days begin to cool.
November ~ Dry Autumn DaysDaily High: 16.9°C (62.4°F)
Daily Low: 9.9°C (49.8°F)
Precipitation: dry (92.5 mm)
Sunshine Duration: normal (146.6 hours)
November is autumn in Tokyo. The weather is dry, cool and pleasant. Tokyo's many parks explode with autumn colors.
December ~ Dry Cool Late Autumn DaysDaily High: 12.4°C (54.3°F)
Daily Low: 5.1°C (41.1°F)
Precipitation: dry (51.0 mm)
Sunshine Duration: sunny (175.0 hours)
December benefits from Tokyo's dry, sunny winters without being as cold as January. It's late autumn in the city. December is the busiest year of the month as people shop for New Years and Christmas. Companies throw bonenkai (forget the year parties) and the city's izakaya fill up.
December is many people's favorite time of the year. Tokyo's Christmas lights are spectacular.