The average dates when frost ends in Kentucky range from mid-April to mid-May as of 2015. There still may be a small chance that frost can occur outside of these dates. The predicted last frost dates vary by region in Kentucky, but are usually around this time frame.
The average dates of last frost are in the range of April 21 to May 10 in Kentucky, according to PlantMaps. This website shows a map of last frost according to early and late date time periods. Meanwhile, VictorySeeds.com shows a chart of average last frost dates by cities in Kentucky.
The University of Kentucky College of Agriculture, Food and Environment website also provides information about last frost dates. A chart on the school's website shows last frost dates by city, coordinates and percentage of chance, with median ranges based on previous observations.