There were 728 households out of which 32.6% had children under the age of 18 living with them, 50.8% were married couples living together, 8.2% had a female householder with no husband present, and 37.2% were non-families. 33.4% of all households were made up of individuals and 17.6% had someone living alone who was 65 years of age or older. The average household size was 2.31 and the average family size was 2.97.
In the city the population was spread out with 25.7% under the age of 18, 7.2% from 18 to 24, 27.1% from 25 to 44, 17.7% from 45 to 64, and 22.3% who were 65 years of age or older. The median age was 38 years. For every 100 females there were 87.3 males. For every 100 females age 18 and over, there were 83.1 males.
The median income for a household in the city was $36,513, and the median income for a family was $45,556. Males had a median income of $31,000 versus $21,824 for females. The per capita income for the city was $18,249. About 4.4% of families and 7.6% of the population were below the poverty line, including 8.3% of those under age 18 and 9.2% of those age 65 or over.
Wilber was declared the official Czech Capital of the United States on July 10, 1987, in a decree signed by then President Ronald Reagan. Wilber hosts the annual Czech Days festival which celebrates the city's Czech heritage.