Irondale, Alabama has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 53.9 °F (low) to 72.7 °F (high). Annual precipitation averages 59.1 Inches. Irondale is located in USDA Plant Hardiness Zone 8b. The growing season typically runs from the last frost around Mar. 21 - Mar. 31 through the first frost around Nov. 11 - Nov. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 35.5 °F | 53.2 °F | 5.23 in. |
| February | 37.9 °F | 57.6 °F | 5.45 in. |
| March | 44.9 °F | 65.7 °F | 5.67 in. |
| April | 52.4 °F | 73.3 °F | 5.26 in. |
| May | 61.6 °F | 80.2 °F | 4.7 in. |
| June | 69.1 °F | 86.3 °F | 4.94 in. |
| July | 72.2 °F | 89.3 °F | 5.19 in. |
| August | 71.5 °F | 88.8 °F | 4.44 in. |
| September | 66.0 °F | 84.4 °F | 4.43 in. |
| October | 54.5 °F | 74.4 °F | 3.48 in. |
| November | 43.8 °F | 63.8 °F | 4.76 in. |
| December | 37.7 °F | 55.5 °F | 5.51 in. |
| Annual | 53.9 °F | 72.7 °F | 59.06 in. |
| Average First Frost Date | Nov. 11 - Nov. 20 |
| Average Last Frost Date | Mar. 21 - Mar. 31 |
| Average Days With Frost | 40-50 Days |
| Plant Hardiness Zone | Zone 8b : 15°F to 20°F |
| Plant Hardiness Zone - 2012 | Zone 8a : 10°F to 15°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |