Dewar, Oklahoma has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 49.1 °F (low) to 72.2 °F (high). Annual precipitation averages 43.9 Inches. Dewar 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 | 27.2 °F | 50.0 °F | 2.1 in. |
| February | 30.7 °F | 54.1 °F | 2.12 in. |
| March | 39.6 °F | 63.3 °F | 3.33 in. |
| April | 47.8 °F | 71.8 °F | 4.46 in. |
| May | 58.0 °F | 79.0 °F | 5.71 in. |
| June | 67.2 °F | 87.5 °F | 4.72 in. |
| July | 70.6 °F | 92.8 °F | 4.08 in. |
| August | 69.3 °F | 93.0 °F | 3.13 in. |
| September | 61.0 °F | 85.5 °F | 4.49 in. |
| October | 49.3 °F | 74.5 °F | 4.01 in. |
| November | 38.9 °F | 62.8 °F | 3.19 in. |
| December | 30.1 °F | 52.1 °F | 2.59 in. |
| Annual | 49.1 °F | 72.2 °F | 43.93 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 7a : 0°F to 5°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |