Grand Junction, Tennessee has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 9.5 °C (low) to 22 °C (high). Annual precipitation averages 1442.2 Millimeters. Grand Junction is located in USDA Plant Hardiness Zone 7b. The growing season typically runs from the last frost around Mar. 21 - Mar. 31 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -1.4 °C | 9.7 °C | 115.32 mm |
| February | 0.2 °C | 12.3 °C | 125.22 mm |
| March | 4.2 °C | 17.1 °C | 144.02 mm |
| April | 8.8 °C | 22.4 °C | 144.53 mm |
| May | 14.2 °C | 26.6 °C | 136.65 mm |
| June | 18.6 °C | 30.7 °C | 118.36 mm |
| July | 20.5 °C | 32.3 °C | 117.86 mm |
| August | 19.6 °C | 32.2 °C | 86.87 mm |
| September | 15.7 °C | 29.3 °C | 100.58 mm |
| October | 9.1 °C | 23.4 °C | 104.9 mm |
| November | 3.6 °C | 16.6 °C | 103.63 mm |
| December | 0.3 °C | 11.2 °C | 144.27 mm |
| Annual | 9.5 °C | 22 °C | 1442.21 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Mar. 21 - Mar. 31 |
| Average Days With Frost | 50-75 Days |
| Plant Hardiness Zone | Zone 7b : -15°C to -12.2°C |
| Plant Hardiness Zone - 2012 | Zone 7b : -15°C to -12.2°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |