Weather will likely play an important role when you plan your trip to Nanseien, but bear in mind that cheaper options are usually available when the weather isn't as good. The hottest months are usually July and August, with an average temperature of 28°C, while the coldest months are January and February, with an average of 20°C. The rainiest months in Nanseien are August, May, September and June, with each month seeing an average of 272 mm of rainfall.