Richardson, Texas has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 13.3 °C (low) to 24.4 °C (high). Annual precipitation averages 1045.7 Millimeters. Richardson 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 | 2 °C | 13.1 °C | 67.56 mm |
| February | 4 °C | 15.4 °C | 77.98 mm |
| March | 8.3 °C | 19.7 °C | 90.93 mm |
| April | 12.6 °C | 24 °C | 90.68 mm |
| May | 17.8 °C | 28.1 °C | 130.3 mm |
| June | 22.2 °C | 32.4 °C | 100.33 mm |
| July | 24.1 °C | 34.8 °C | 54.1 mm |
| August | 23.9 °C | 34.9 °C | 58.42 mm |
| September | 19.8 °C | 31.2 °C | 83.06 mm |
| October | 13.6 °C | 25.6 °C | 122.68 mm |
| November | 7.8 °C | 19.1 °C | 80.52 mm |
| December | 3.1 °C | 14.2 °C | 89.15 mm |
| Annual | 13.3 °C | 24.4 °C | 1045.71 mm |
| 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 : -9.4°C to -6.7°C |
| Plant Hardiness Zone - 2012 | Zone 8a : -12.2°C to -9.4°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |