Princeton, Kentucky has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 8.9 °C (low) to 20.5 °C (high). Annual precipitation averages 1287.3 Millimeters. Princeton is located in USDA Plant Hardiness Zone 7a. The growing season typically runs from the last frost around Apr. 1 - Apr. 10 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -2.8 °C | 7.1 °C | 95.76 mm |
| February | -1.2 °C | 9.7 °C | 100.84 mm |
| March | 3.2 °C | 15 °C | 118.11 mm |
| April | 8.4 °C | 21.2 °C | 129.03 mm |
| May | 13.9 °C | 25.7 °C | 132.33 mm |
| June | 18.6 °C | 29.8 °C | 120.4 mm |
| July | 20.4 °C | 31.5 °C | 108.71 mm |
| August | 19.4 °C | 31.4 °C | 77.72 mm |
| September | 15.2 °C | 28.4 °C | 83.31 mm |
| October | 8.9 °C | 21.9 °C | 98.04 mm |
| November | 3.1 °C | 14.9 °C | 103.12 mm |
| December | -0.9 °C | 8.9 °C | 119.89 mm |
| Annual | 8.9 °C | 20.5 °C | 1287.26 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 1 - Apr. 10 |
| Average Days With Frost | 50-75 Days |
| Plant Hardiness Zone | Zone 7a : -17.8°C to -15°C |
| Plant Hardiness Zone - 2012 | Zone 6b : -20.6°C to -17.8°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |