In recent years, average temperatures in the county seat of Taylorville have ranged from a low of 16 °F (−9 °C) in January to a high of 86 °F (30 °C) in July, although a record low of −23 °F (−31 °C) was recorded in January 1994 and a record high of 104 °F (40 °C) was recorded in August 1988. Average monthly precipitation ranged from 1.78 inches (45 mm) in January to 3.77 inches (96 mm) in May.
There were 13,921 households out of which 30.40% had children under the age of 18 living with them, 55.30% were married couples living together, 9.10% had a female householder with no husband present, and 31.90% were non-families. 28.40% of all households were made up of individuals and 14.70% had someone living alone who was 65 years of age or older. The average household size was 2.41 and the average family size was 2.94.
In the county the population was spread out with 24.10% under the age of 18, 7.60% from 18 to 24, 28.10% from 25 to 44, 23.00% from 45 to 64, and 17.20% who were 65 years of age or older. The median age was 39 years. For every 100 females there were 99.60 males. For every 100 females age 18 and over, there were 97.30 males.
The median income for a household in the county was $36,561, and the median income for a family was $43,342. Males had a median income of $32,344 versus $22,522 for females. The per capita income for the county was $17,937. About 6.50% of families and 9.50% of the population were below the poverty line, including 13.40% of those under age 18 and 10.20% of those age 65 or over.