Lethbridge, Alberta climate data is summarized below. Average annual temperatures range from 0.3 °C (low) to 12.6 °C (high). Annual precipitation averages 350 Millimeters. Lethbridge is located in USDA Plant Hardiness Zone 4b. The growing season typically runs from the last frost around May 11 - May 20 through the first frost around Sep.11 - Sep. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -10.09 °C | -0.1 °C | 0 mm |
| February | -9.01 °C | 1.8 °C | 0 mm |
| March | -4.41 °C | 7.07 °C | 3 mm |
| April | -0.57 °C | 12.07 °C | 37 mm |
| May | 4.53 °C | 17.7 °C | 65 mm |
| June | 8.89 °C | 21.63 °C | 100 mm |
| July | 11.85 °C | 26.16 °C | 49 mm |
| August | 10.47 °C | 25.81 °C | 32 mm |
| September | 6.45 °C | 21.27 °C | 34 mm |
| October | 1.49 °C | 13.88 °C | 28 mm |
| November | -4.94 °C | 5.54 °C | 2 mm |
| December | -11.45 °C | -1.33 °C | 0 mm |
| Annual | 0.3 °C | 12.6 °C | 350 mm |
| Average First Frost Date | Sep.11 - Sep. 20 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 4b : -31.7°C to -28.9°C |
| Current Drought Conditions | Moderate Drought |