Climate

Putnam County experiences a temperate climate with generally mild winters and moderately humid summers. Cold weather comes mostly from the northwest, originating in western Canada, while heat and humidity come from Gulf-coast air masses. Prevailing winds during the summer months are from the southwest; prevailing winds in the winter are from the northwest.

Putnam County is near the border of North American Agricultural Zones 5 and 6. The Zone 6 hardiness band, in which Greencastle is located, is hardy for most common North American fruit, shrubs, and ornamentals. The growing season is 175 days.

Temperature

Minimum Average: 17°F in January

Maximum Average: 84°F in July

 Precipitation

Average Annual: 45.53 inches / 115.6 cm

 Snow/Sleet

Average Annual: 23.0 inches / 58.4 cm

 Cooling Degree Days

Annual (65°F Base): 804

 Heating Degree Days

Annual (65°F Base): 5,938

 Percentage of Available Sunshine

January & December: Approx. 40%

June, July, August & September: Approx. 70%

Source

Data based on Weather Station ID: 123513 – Greencastle 3 SW.

30 Year Normals – 1991 to 2020. The next update of 30 Year Normals will be 2001 to 2030.

Indiana State Climate Office at Purdue University

Updated: 5/2024