If you’re looking forward to lots of outings with your partner, take a look at these details about year-round temperatures in Tsukioka Onsen: The hottest months are usually August and July, with an average temperature of 23°C, while the coldest months are February and January, with an average of 3°C. The rainiest months in Tsukioka Onsen are July, December, January and August, with each month seeing an average of 257 mm of rainfall.