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

[2] Per Japanese census data,[3] the population of Nishitokyo increased rapidly in the 1950s and 1960s and has continued to grow at a slower pace in recent decades.

In the post-Meiji Restoration cadastral reform of July 22, 1878, the area became part of Kitadachi District in Saitama Prefecture.

Nishitokyo has a mayor-council form of government with a directly elected mayor and a unicameral city council of 28 members.

In terms of national politics, the city is part of Tokyo 19th district of the lower house of the Diet of Japan.