Massac, Kentucky has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 48 °F (low) to 68.5 °F (high). Annual precipitation averages 50.9 Inches. Massac 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 | 27.5 °F | 44.6 °F | 4.03 in. |
| February | 30.2 °F | 49.4 °F | 3.74 in. |
| March | 37.9 °F | 58.9 °F | 4.81 in. |
| April | 47.1 °F | 69.5 °F | 5.2 in. |
| May | 57.2 °F | 78.0 °F | 5.27 in. |
| June | 65.7 °F | 85.7 °F | 4.58 in. |
| July | 69.0 °F | 88.6 °F | 4.15 in. |
| August | 66.8 °F | 88.1 °F | 3.0 in. |
| September | 59.2 °F | 82.4 °F | 3.53 in. |
| October | 47.6 °F | 71.3 °F | 3.85 in. |
| November | 37.4 °F | 58.1 °F | 4.22 in. |
| December | 30.5 °F | 47.8 °F | 4.52 in. |
| Annual | 48 °F | 68.5 °F | 50.9 in. |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 1 - Apr. 10 |
| Average Days With Frost | 75-100 Days |
| Plant Hardiness Zone | Zone 7a : 0°F to 5°F |
| Plant Hardiness Zone - 2012 | Zone 7a : 0°F to 5°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |