Jonesboro is an unincorporated community in Coryell and Hamilton counties in Central Texas. The Coryell County portion of the community is part of the Killeen–Temple–Fort Hood Metropolitan Statistical Area.The United States Postal Service operates the Jonesboro Post Office.The climate in this area is characterized by hot, humid summers and generally mild to cool winters. According to the Köppen Climate Classification system, Jonesboro has a humid subtropical climate, abbreviated "Cfa" on climate maps.