Chelsea, Oklahoma has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 47.5 °F (low) to 70.3 °F (high). Annual precipitation averages 44.5 Inches. Chelsea 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 | 25.1 °F | 47.0 °F | 2.02 in. |
| February | 28.4 °F | 51.7 °F | 2.08 in. |
| March | 37.1 °F | 61.0 °F | 3.47 in. |
| April | 46.2 °F | 70.3 °F | 4.43 in. |
| May | 56.6 °F | 77.6 °F | 6.31 in. |
| June | 65.8 °F | 86.1 °F | 5.19 in. |
| July | 69.9 °F | 91.5 °F | 3.74 in. |
| August | 68.2 °F | 91.5 °F | 3.32 in. |
| September | 59.9 °F | 83.9 °F | 4.28 in. |
| October | 47.8 °F | 72.5 °F | 3.94 in. |
| November | 36.9 °F | 60.7 °F | 3.19 in. |
| December | 28.1 °F | 49.5 °F | 2.48 in. |
| Annual | 47.5 °F | 70.3 °F | 44.45 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 | Normal |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |