When to go & Weather:
Best time to visit Japan is April to May and October to November.
The summer months are very hot and humid. If you visit in June to August, don't forget to take an umbrella and a raincoat.
The winter months tend to be cold, with snowfalls in some places. You should therefore take warm clothing.
April, May, October and November are the mildest and clearest months. Although the temperature is good, don't forget to take something to wrap up in, particularly at night (especially if travelling in November).
September is typhoon month and is therefore not a good time to travel to Okinawa, the Izu-shoto and Ogasawara-shoto.
Consult the weather forecast for the next 9 days in Tokyo here.