The modern city of Aso was established on February 11, 2005, from the merger of the former town of Aso, absorbing the town of Ichinomiya, and the village of Namino (all from Aso District).
As of March 31, 2017, the city has an estimated population of 27,039, with 11,355 households[1] and a population density of 72 people per km2. The total area is 376.25 km2.
Aso has a humid subtropical climate (Köppen climate classificationCfa) with hot, humid summers and cool winters. There is significant precipitation throughout the year, especially during June and July. The average annual temperature in Aso is 13.2 °C (55.8 °F). The average annual rainfall is 3,009.6 mm (118.49 in) with June as the wettest month. The temperatures are highest on average in August, at around 24.2 °C (75.6 °F), and lowest in January, at around 2.0 °C (35.6 °F).[3] The highest temperature ever recorded in Aso was 34.9 °C (94.8 °F) on 11 August 2016; the coldest temperature ever recorded was −14.8 °C (5.4 °F) on 25 January 1998.[4]
Climate data for Aso (1991−2020 normals, extremes 1978−present)