Oswego, South Carolina has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 51.7 °F (low) to 75 °F (high). Annual precipitation averages 47.8 Inches. Oswego is located in USDA Plant Hardiness Zone 8b. The growing season typically runs from the last frost around Mar. 11 - Mar. 20 through the first frost around Nov. 11 - Nov. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 33.7 °F | 56.6 °F | 3.71 in. |
| February | 35.9 °F | 60.0 °F | 3.51 in. |
| March | 41.7 °F | 67.5 °F | 3.65 in. |
| April | 50.1 °F | 76.2 °F | 3.23 in. |
| May | 59.2 °F | 82.8 °F | 3.62 in. |
| June | 67.4 °F | 88.7 °F | 5.16 in. |
| July | 70.6 °F | 91.5 °F | 5.26 in. |
| August | 69.3 °F | 89.8 °F | 5.08 in. |
| September | 63.6 °F | 84.9 °F | 4.32 in. |
| October | 52.1 °F | 76.0 °F | 3.72 in. |
| November | 41.1 °F | 66.4 °F | 2.83 in. |
| December | 36.1 °F | 59.0 °F | 3.67 in. |
| Annual | 51.7 °F | 75 °F | 47.76 in. |
| Average First Frost Date | Nov. 11 - Nov. 20 |
| Average Last Frost Date | Mar. 11 - Mar. 20 |
| 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 | Severe Drought |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |