Newmarket, Ontario climate data is summarized below. Average annual temperatures range from 37.3 °F (low) to 54.4 °F (high). Annual precipitation averages 32.4 Inches. Newmarket is located in USDA Plant Hardiness Zone 5b. 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 | -23.3 °F | -19 °F | 304.8 in. |
| February | -23.9 °F | -19.3 °F | 101.6 in. |
| March | -20.6 °F | -15.5 °F | 1219.2 in. |
| April | -17 °F | -11.2 °F | 1854.2 in. |
| May | -13.5 °F | -7 °F | 2692.4 in. |
| June | -10.7 °F | -4.5 °F | 2641.6 in. |
| July | -9.2 °F | -3 °F | 3302 in. |
| August | -9.6 °F | -3.6 °F | 3200.4 in. |
| September | -12 °F | -6.1 °F | 1803.4 in. |
| October | -14.9 °F | -10.1 °F | 1651 in. |
| November | -18.1 °F | -13.8 °F | 1270 in. |
| December | -21.1 °F | -17.5 °F | 889 in. |
| Annual | 37.3 °F | 54.4 °F | 32.44 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 5b : -15°F to -10°F |
| Current Drought Conditions | Normal |