Simms, Oklahoma has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 10.4 °C (low) to 22.3 °C (high). Annual precipitation averages 1161.8 Millimeters. Simms 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 | -1.9 °C | 9.8 °C | 65.02 mm |
| February | 0.2 °C | 12.4 °C | 57.66 mm |
| March | 4.9 °C | 17.1 °C | 97.28 mm |
| April | 9.7 °C | 22.1 °C | 113.79 mm |
| May | 15.2 °C | 26.1 °C | 147.32 mm |
| June | 19.9 °C | 30.8 °C | 118.36 mm |
| July | 22.2 °C | 33.8 °C | 91.19 mm |
| August | 21.6 °C | 33.7 °C | 84.84 mm |
| September | 17.2 °C | 29.5 °C | 117.6 mm |
| October | 10.8 °C | 23.5 °C | 103.89 mm |
| November | 4.9 °C | 17.1 °C | 89.92 mm |
| December | 0 °C | 11.3 °C | 74.93 mm |
| Annual | 10.4 °C | 22.3 °C | 1161.8 mm |
| 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 : -15°C to -12.2°C |
| Plant Hardiness Zone - 2012 | Zone 7a : -17.8°C to -15°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |