Louisville’s climate is described as "moist-continental."  Winters are moderately cold with temperatures rarely below zero degrees Fahrenheit, with January being the coldest month. The average annual snowfall is about 17 inches. Summers are hot (although rarely above 100 degrees Fahrenheit) and humid, with July being the hottest month. Spring and summer months are characterized by changeable, wet weather. March has the greatest total rainfall. Yearly precipitation is approximately 43 inches. The driest month is October.

Jefferson County has eleven major stream systems: Mill Creek, Pond Creek, South Fork Beargrass Creek, Middle Fork Beargrass Creek, Muddy Fork Beargrass Creek, Goose Creek, Harrods Creek, Floyds Fork, Cedar Creek, Pennsylvania Run, and Ohio River. Approximately 790 miles of streams are found within these six stream systems. The land drained by each of these streams is called a "watershed."