Maynooth, Ontario climate data is summarized below. Average annual temperatures range from 29.7 °F (low) to 50.2 °F (high). Annual precipitation averages 22.6 Inches. Maynooth is located in USDA Plant Hardiness Zone 4a. The growing season typically runs from the last frost around May 21 - May 31 through the first frost around Sep.11 - Sep. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -26.5 °F | -20.7 °F | 0 in. |
| February | -26.9 °F | -20.4 °F | 0 in. |
| March | -23.1 °F | -16.7 °F | 254 in. |
| April | -19.1 °F | -12.3 °F | 1447.8 in. |
| May | -15.4 °F | -7.8 °F | 1828.8 in. |
| June | -12.4 °F | -5.6 °F | 1930.4 in. |
| July | -11.2 °F | -4.3 °F | 2235.2 in. |
| August | -11.6 °F | -4.9 °F | 2082.8 in. |
| September | -14.3 °F | -7.3 °F | 1778 in. |
| October | -16.9 °F | -11.4 °F | 2006.6 in. |
| November | -20.3 °F | -15.2 °F | 1016 in. |
| December | -24.1 °F | -19.3 °F | 0 in. |
| Annual | 29.7 °F | 50.2 °F | 22.58 in. |
| Average First Frost Date | Sep.11 - Sep. 20 |
| Average Last Frost Date | May 21 - May 31 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 4a : -30°F to -25°F |
| Current Drought Conditions | Normal |