Which quality is characteristic of Kentucky's humid subtropical climate?

Kentucky's humid subtropical climate is primarily characterized by hot, humid summers. This climate type is typically marked by high temperatures and significant moisture, leading to warm summer conditions that can be quite oppressive due to humidity levels. The presence of moisture in the air contributes to thunderstorms and higher heat indices during the summer months.

In contrast, the other options do not accurately reflect the climate of Kentucky. Cold winters with heavy snowfall suggest a more continental or subarctic climate, which is not representative of Kentucky’s weather patterns. Mild, dry seasons imply a lack of humidity and precipitation, which does not apply to the humid subtropical climate of the region. Lastly, arid desert conditions are completely inconsistent with Kentucky's environment, which receives ample rainfall and has a diverse ecosystem.

Thus, the hallmark of this climate in Kentucky is the combination of heat and humidity experienced during the summer.