Penetanguishene, Ontario climate data is summarized below. Average annual temperatures range from 37.2 °F (low) to 51.9 °F (high). Annual precipitation averages 8.6 Inches. Penetanguishene is located in USDA Plant Hardiness Zone 5b. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -23.6 °F | -19.3 °F | 101.6 in. |
| February | -24.4 °F | -19.8 °F | 0 in. |
| March | -21.2 °F | -16.6 °F | 254 in. |
| April | -17.5 °F | -12.5 °F | 482.6 in. |
| May | -14.2 °F | -8.5 °F | 584.2 in. |
| June | -11 °F | -5.8 °F | 762 in. |
| July | -9.1 °F | -4.3 °F | 1143 in. |
| August | -9.1 °F | -4.5 °F | 990.6 in. |
| September | -11.3 °F | -6.6 °F | 533.4 in. |
| October | -14.1 °F | -10.3 °F | 381 in. |
| November | -17.5 °F | -13.9 °F | 228.6 in. |
| December | -20.9 °F | -17.7 °F | 76.2 in. |
| Annual | 37.2 °F | 51.9 °F | 8.59 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 5b : -15°F to -10°F |
| Current Drought Conditions | Normal |