Flat, Texas has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 55.8 °F (low) to 78.4 °F (high). Annual precipitation averages 34.6 Inches. Flat is located in USDA Plant Hardiness Zone 8b. The growing season typically runs from the last frost around Mar. 1 - Mar. 10 through the first frost around Nov. 21 - Nov. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 36.7 °F | 59.8 °F | 2.24 in. |
| February | 40.5 °F | 63.5 °F | 2.38 in. |
| March | 47.5 °F | 70.4 °F | 3.1 in. |
| April | 55.0 °F | 78.1 °F | 2.73 in. |
| May | 63.8 °F | 84.5 °F | 4.41 in. |
| June | 70.8 °F | 91.5 °F | 3.52 in. |
| July | 73.3 °F | 95.5 °F | 1.88 in. |
| August | 73.1 °F | 96.3 °F | 2.42 in. |
| September | 66.9 °F | 89.9 °F | 2.75 in. |
| October | 56.7 °F | 80.4 °F | 4.03 in. |
| November | 46.3 °F | 69.3 °F | 2.64 in. |
| December | 38.6 °F | 61.1 °F | 2.52 in. |
| Annual | 55.8 °F | 78.4 °F | 34.62 in. |
| Average First Frost Date | Nov. 21 - Nov. 30 |
| Average Last Frost Date | Mar. 1 - Mar. 10 |
| Average Days With Frost | 20-30 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 | Normal |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |