Rock Island, Oklahoma has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 49.7 °F (low) to 73 °F (high). Annual precipitation averages 49.6 Inches. Rock Island 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 Nov. 1 - Nov. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 28.3 °F | 50.9 °F | 3.16 in. |
| February | 32.1 °F | 55.6 °F | 2.9 in. |
| March | 40.0 °F | 64.1 °F | 4.3 in. |
| April | 48.5 °F | 72.9 °F | 4.97 in. |
| May | 58.4 °F | 80.0 °F | 6.02 in. |
| June | 67.2 °F | 88.4 °F | 4.33 in. |
| July | 70.9 °F | 93.4 °F | 3.65 in. |
| August | 69.5 °F | 93.1 °F | 3.49 in. |
| September | 61.9 °F | 86.0 °F | 4.33 in. |
| October | 49.6 °F | 75.2 °F | 4.15 in. |
| November | 39.2 °F | 63.4 °F | 4.54 in. |
| December | 31.3 °F | 53.4 °F | 3.79 in. |
| Annual | 49.7 °F | 73 °F | 49.63 in. |
| Average First Frost Date | Nov. 1 - Nov. 10 |
| Average Last Frost Date | Mar. 21 - Mar. 31 |
| Average Days With Frost | 50-75 Days |
| Plant Hardiness Zone | Zone 7b : 5°F to 10°F |
| Plant Hardiness Zone - 2012 | Zone 7b : 5°F to 10°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |