Planning for the weather is an important factor for making your trip to Agematsu a success, especially when you're splurging. The hottest months are usually August and July, with an average temperature of 19°C, while the coldest months are January and February, with an average of 0°C. The rainiest months in Agematsu are July, June, September and August, with each month seeing an average of 295 mm of rainfall.