The temperature in autumn in Japan is just right: not too hot, not too cold, but complimented by a fair amount of sunshine. You miss the humid, hot summer. This season can be survived only with the help of ‘cooling gel’ and the occasional flight into a convenience store with maximum force airco. Also, you can evade winter, which is also not too bad, but it can get cold, and you run the risk of getting stuck in your hotel because public traffic stops running when snow falls (which is something my friend experienced for some 3 days in winter 2013). Spring is another popular season to visit the country because of the sakura blooming. But the colourful sights of autumn can definitely compete with that if you ask me. In autumn, you can enjoy the lingering summer heat and still walk outside at night with only a t-shirt on (and maybe a pair of pants if you want to avoid getting arrested).
Image courtesy of amazon.co.jp