New Ulm, Texas has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 14.4 °C (low) to 26.1 °C (high). Annual precipitation averages 1095 Millimeters. New Ulm is located in USDA Plant Hardiness Zone 9a. 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 | 4.9 °C | 16.3 °C | 87.38 mm |
| February | 6.9 °C | 18.3 °C | 71.37 mm |
| March | 10.5 °C | 21.9 °C | 84.58 mm |
| April | 14.1 °C | 25.8 °C | 85.85 mm |
| May | 18.4 °C | 29.4 °C | 119.89 mm |
| June | 22.2 °C | 32.8 °C | 107.19 mm |
| July | 23 °C | 34.1 °C | 60.96 mm |
| August | 23 °C | 35.7 °C | 85.85 mm |
| September | 20.2 °C | 32.4 °C | 91.95 mm |
| October | 14.9 °C | 27.2 °C | 114.3 mm |
| November | 9.3 °C | 21.6 °C | 96.52 mm |
| December | 5.7 °C | 17.4 °C | 89.15 mm |
| Annual | 14.4 °C | 26.1 °C | 1094.99 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 9a : -6.7°C to -3.9°C |
| Plant Hardiness Zone - 2012 | Zone 8b : -9.4°C to -6.7°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |