Planning for the weather is a good way to make your trip to Nagoya relaxing and enjoyable, especially when you’re splurging. The hottest months are usually August and July, with an average temperature of 25°C, while the coldest months are January and February, with an average of 6°C. The rainiest months in Nagoya are July, September, June and October, with each month seeing an average of 239 mm of rainfall.