Rienzi, Mississippi has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 9.9 °C (low) to 22.2 °C (high). Annual precipitation averages 1483.1 Millimeters. Rienzi is located in USDA Plant Hardiness Zone 8a. 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 | -0.9 °C | 10.2 °C | 129.54 mm |
| February | 0.7 °C | 12.8 °C | 127.25 mm |
| March | 4.7 °C | 17.7 °C | 138.68 mm |
| April | 9.3 °C | 22.7 °C | 139.7 mm |
| May | 14.7 °C | 26.8 °C | 139.19 mm |
| June | 19.1 °C | 30.6 °C | 119.89 mm |
| July | 20.9 °C | 32.3 °C | 114.3 mm |
| August | 20.1 °C | 32.1 °C | 103.38 mm |
| September | 16.2 °C | 29.3 °C | 109.47 mm |
| October | 9.3 °C | 23.4 °C | 99.06 mm |
| November | 3.7 °C | 16.9 °C | 110.49 mm |
| December | 0.8 °C | 11.7 °C | 152.15 mm |
| Annual | 9.9 °C | 22.2 °C | 1483.1 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 8a : -12.2°C to -9.4°C |
| Plant Hardiness Zone - 2012 | Zone 7b : -15°C to -12.2°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |