Whitby, Ontario climate data is summarized below. Average annual temperatures range from 39.1 °F (low) to 55.6 °F (high). Annual precipitation averages 36.7 Inches. Whitby 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 | -22.5 °F | -18.3 °F | 558.8 in. |
| February | -23.1 °F | -18.5 °F | 533.4 in. |
| March | -20 °F | -15 °F | 1727.2 in. |
| April | -16.4 °F | -11 °F | 2616.2 in. |
| May | -13.1 °F | -7.1 °F | 2463.8 in. |
| June | -10.2 °F | -4.4 °F | 2895.6 in. |
| July | -8.8 °F | -2.9 °F | 2692.4 in. |
| August | -9.1 °F | -3.3 °F | 2641.6 in. |
| September | -11.5 °F | -5.7 °F | 1854.2 in. |
| October | -14.4 °F | -9.7 °F | 2362.2 in. |
| November | -17.6 °F | -13.2 °F | 1752.6 in. |
| December | -20.4 °F | -16.8 °F | 1600.2 in. |
| Annual | 39.1 °F | 55.6 °F | 36.74 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 6a : -10°F to -5°F |
| Current Drought Conditions | Normal |