There were 108 households out of which 27.8% had children under the age of 18 living with them, 75.9% were married couples living together, 0.9% had a female householder with no husband present, and 21.3% were non-families. 19.4% of all households were made up of individuals and 5.6% had someone living alone who was 65 years of age or older. The average household size was 2.53 and the average family size was 2.86. In the city, the population was spread out with 22.7% under the age of 18, 4.4% from 18 to 24, 21.6% from 25 to 44, 31.5% from 45 to 64, and 19.8% who were 65 years of age or older. The median age was 46 years. For every 100 females, there were 103.7 males. For every 100 females age 18 and over, there were 113.1 males. The median income for a household in the city was $48,333, and the median income for a family was $52,250. Males had a median income of $50,972 versus $27,500 for females. The per capita income for the city was $18,970. None of the families and 3.8% of the population were living below the poverty line, including no under eighteens and 5.7% of those over 64. This climatic region is typified by large seasonal temperature differences, with warm to hot (and often humid) summers and cold (sometimes severely cold) winters. According to the Köppen Climate Classification system, Riverdale has a humid continental climate, abbreviated "Dfb" on climate maps. Riverdale High School was closed in the 1980s and consolidated with the high school in nearby Underwood, North Dakota. The high school athletic teams were named the Knights and the school colors were red and white. The school fielded a nine-man football team. The team played local nine-man teams including Stanton, Goodrich, White Shield and Bowdon.