As of the census of 2000, there were 9,859 people, 3,991 households, and 2,187 families residing in the city. The population density was 1,699.3 people per square mile (656.3/km²). There were 4,468 housing units at an average density of 770.1/sq mi (297.4/km²). The racial makeup of the city was 87.16% White, 1.95% African American, 4.97% Native American, 1.29% Asian, 0.06% Pacific Islander, 1.76% from other races, and 2.81% from two or more races. Hispanic or Latino of any race were 4.30% of the population.
There were 3,991 households out of which 25.8% had children under the age of 18 living with them, 42.5% were married couples living together, 9.0% had a female householder with no husband present, and 45.2% were non-families. 31.6% of all households were made up of individuals and 8.3% had someone living alone who was 65 years of age or older. The average household size was 2.27 and the average family size was 2.96.
In the city the population was spread out with 19.8% under the age of 18, 32.1% from 18 to 24, 22.4% from 25 to 44, 16.2% from 45 to 64, and 9.4% who were 65 years of age or older. The median age was 24 years. For every 100 females there were .2 males. For every 100 females age 18 and over, there were 91.2 males. The median income for a household in the city was $26,908, and the median income for a family was $41,401. Males had a median income of $29,683 versus $20,833 for females. The per capita income for the city was $16,046. About 11.8% of families and 21.7% of the population were below the poverty line, including 19.1% of those under age 18 and 11.8% of those age 65 or over.
Weatherford was for many years on a main line of the now defunct Rock Island Railroad, which is still in operation by a different owner. With the advent of the automobile, the city was initially located on State Highway 3 starting in the early 1920s, which was redesignated as U.S. Route 66 in 1926 and paved entirely across Western Oklahoma by 1932. Route 66, which followed Main Street through the city, was lined with various tourist businesses including cafes, motels and gasoline stations like most other cities along the highway. Several blocks of Main Street were also paved in brick until the mid 1950s when it was widened to a four-lane thoroughfare. Interstate 40 was completed east and west of the city in 1960 generally paralleling the old U.S. 66 alignment, which was retained as frontage road. The I-40 bypass skirting Weatherford to the south was completed in July, 1970 the same day the I-40 bypass was opened to traffic 15 miles (24 km) to the west at Clinton and followed shortly thereafter by bypasses at Elk City and Sayre. In addition to Route 66 and I-40, Weatheford is also served by north-south State Highway 54.