14 days in December, one city and one infant

Hi! We would like to spend 14 days in Japan in the first half of December. We will have a 8 months old child. We have been to Tokyo, Kyoto, Nikko, Nara, Hiroshima and osaka last year so we are not looking for a classic touristic destination but rather for a city which is fun to walk around with a child, not too snowy given the period and not too difficult to navigate given we are not staying for long. Any suggestions??