Milton, Ontario climate data is summarized below. Average annual temperatures range from 39.9 °F (low) to 56.3 °F (high). Annual precipitation averages 35.8 Inches. Milton is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -22.3 °F | -18.4 °F | 482.6 in. |
| February | -23 °F | -18.6 °F | 711.2 in. |
| March | -19.8 °F | -14.9 °F | 1828.8 in. |
| April | -16.3 °F | -10.8 °F | 2514.6 in. |
| May | -12.8 °F | -6.8 °F | 2616.2 in. |
| June | -9.9 °F | -4.1 °F | 2463.8 in. |
| July | -8.4 °F | -2.4 °F | 2413 in. |
| August | -8.7 °F | -2.9 °F | 2641.6 in. |
| September | -11.1 °F | -5.3 °F | 2082.8 in. |
| October | -14.2 °F | -9.4 °F | 2006.6 in. |
| November | -17.4 °F | -13.1 °F | 1752.6 in. |
| December | -20.2 °F | -16.9 °F | 1549.4 in. |
| Annual | 39.9 °F | 56.3 °F | 35.75 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 6a : -10°F to -5°F |
| Current Drought Conditions | Normal |