Tanabe has a humid subtropical climate (Köppen Cfa) characterized by warm summers and cool winters with light to no snowfall.

During the Edo period, it was part of the holdings of Kishū Domain ruled by a cadet branch of the Tokugawa clan through a hereditary karō based at Tanabe Castle.

Tanabe continued to expand through annexation of neighboring municipalities: the villages of Inari, Shimaakizu, Maro in 1950, Shinjo in 1954, Nishi-Tonda in 1955, and the town of Muro in 1958.

Tanabe has a mayor-council form of government with a directly elected mayor and a unicameral city council of 20 members.

In terms of national politics, the city is part of Wakayama 3rd district of the lower house of the Diet of Japan.

Agriculture plays a major role in the economy, with production of umeboshi pickled plums, and the cultivation of various varieties of oranges and other citrus fruits.