Orillia, Ontario climate data is summarized below. Average annual temperatures range from 35.7 °F (low) to 52.1 °F (high). Annual precipitation averages 20 Inches. Orillia 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 | -24.4 °F | -19.7 °F | 177.8 in. |
| February | -25 °F | -19.9 °F | 0 in. |
| March | -21.5 °F | -16.4 °F | 635 in. |
| April | -17.6 °F | -12 °F | 939.8 in. |
| May | -14.1 °F | -7.9 °F | 1295.4 in. |
| June | -11.1 °F | -5.4 °F | 1828.8 in. |
| July | -9.4 °F | -3.8 °F | 2540 in. |
| August | -9.6 °F | -4.3 °F | 2590.8 in. |
| September | -12 °F | -6.7 °F | 1270 in. |
| October | -14.9 °F | -10.5 °F | 838.2 in. |
| November | -18.3 °F | -14.2 °F | 508 in. |
| December | -21.7 °F | -18.1 °F | 279.4 in. |
| Annual | 35.7 °F | 52.1 °F | 20.01 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 5b : -15°F to -10°F |
| Current Drought Conditions | Normal |