Arnprior, Ontario climate data is summarized below. Average annual temperatures range from 35.1 °F (low) to 53.7 °F (high). Annual precipitation averages 19.1 Inches. Arnprior is located in USDA Plant Hardiness Zone 5a. The growing season typically runs from the last frost around May 11 - May 20 through the first frost around Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -25.3 °F | -20.1 °F | 0 in. |
| February | -25.3 °F | -19.7 °F | 0 in. |
| March | -21.9 °F | -16.1 °F | 431.8 in. |
| April | -17.2 °F | -10.8 °F | 914.4 in. |
| May | -13.6 °F | -6.4 °F | 1193.8 in. |
| June | -10.7 °F | -4.2 °F | 1930.4 in. |
| July | -9.4 °F | -3.1 °F | 2616.2 in. |
| August | -9.8 °F | -3.6 °F | 2260.6 in. |
| September | -12.4 °F | -6.2 °F | 1346.2 in. |
| October | -15.3 °F | -10.2 °F | 939.8 in. |
| November | -18.6 °F | -14.1 °F | 457.2 in. |
| December | -22.6 °F | -18.5 °F | 228.6 in. |
| Annual | 35.1 °F | 53.7 °F | 19.1 in. |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 5a : -20°F to -15°F |
| Current Drought Conditions | Normal |