Castor, Alberta climate data is summarized below. Average annual temperatures range from -2.4 °C (low) to 8.8 °C (high). Annual precipitation averages 434 Millimeters. Castor is located in USDA Plant Hardiness Zone 3b. 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 | -15.41 °C | -6.89 °C | 0 mm |
| February | -14.7 °C | -5.64 °C | 0 mm |
| March | -8.61 °C | 1.05 °C | 0 mm |
| April | -2.7 °C | 8.98 °C | 33 mm |
| May | 3.54 °C | 17.34 °C | 59 mm |
| June | 8.65 °C | 21.05 °C | 111 mm |
| July | 11.32 °C | 24.3 °C | 93 mm |
| August | 9.64 °C | 23.51 °C | 70 mm |
| September | 4.96 °C | 19.13 °C | 42 mm |
| October | -0.49 °C | 11 °C | 26 mm |
| November | -8.55 °C | -0.45 °C | 0 mm |
| December | -16.27 °C | -8.11 °C | 0 mm |
| Annual | -2.4 °C | 8.8 °C | 434 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 3b : -37.2°C to -34.4°C |
| Current Drought Conditions | Normal |