Costilla, New Mexico has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 27 °F (low) to 59.4 °F (high). Annual precipitation averages 12.6 Inches. Costilla is located in USDA Plant Hardiness Zone 5a. The growing season typically runs from the last frost around May 11 - May 20 through the first frost around Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 5.1 °F | 36.1 °F | 0.57 in. |
| February | 11.8 °F | 40.9 °F | 0.51 in. |
| March | 19.9 °F | 50.6 °F | 0.87 in. |
| April | 26.0 °F | 58.6 °F | 0.96 in. |
| May | 34.3 °F | 67.4 °F | 1.13 in. |
| June | 42.1 °F | 78.0 °F | 0.74 in. |
| July | 48.0 °F | 80.9 °F | 1.82 in. |
| August | 46.4 °F | 78.9 °F | 1.85 in. |
| September | 39.1 °F | 73.2 °F | 1.41 in. |
| October | 27.9 °F | 62.4 °F | 1.11 in. |
| November | 16.5 °F | 48.8 °F | 0.8 in. |
| December | 6.7 °F | 36.9 °F | 0.82 in. |
| Annual | 27 °F | 59.4 °F | 12.59 in. |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | Over 180 Days |
| Plant Hardiness Zone | Zone 5a : -20°F to -15°F |
| Plant Hardiness Zone - 2012 | Zone 5a : -20°F to -15°F |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |