Weather is probably a major factor when you plan your trip to Toshima, but bear in mind that cheaper options are usually available when the weather isn't as good. The hottest months are usually August and July, with an average temperature of 27°C, while the coldest months are January and February, with an average of 16°C. The rainiest months in Toshima are June, July, September and May, with each month seeing an average of 381 mm of rainfall.