Toronto, Iowa has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 3.8 °C (low) to 15.2 °C (high). Annual precipitation averages 964.9 Millimeters. Toronto is located in USDA Plant Hardiness Zone 5a. 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 | -11 °C | -1.7 °C | 35.56 mm |
| February | -9.1 °C | 0.8 °C | 41.4 mm |
| March | -2.8 °C | 8.1 °C | 61.98 mm |
| April | 3.3 °C | 15.9 °C | 97.28 mm |
| May | 9.9 °C | 22.2 °C | 115.82 mm |
| June | 15.5 °C | 27.3 °C | 125.98 mm |
| July | 17.3 °C | 29 °C | 109.73 mm |
| August | 16.1 °C | 28.1 °C | 106.17 mm |
| September | 11.2 °C | 24.7 °C | 94.23 mm |
| October | 4.8 °C | 17.6 °C | 75.44 mm |
| November | -1.8 °C | 8.8 °C | 56.9 mm |
| December | -7.4 °C | 1.4 °C | 44.45 mm |
| Annual | 3.8 °C | 15.2 °C | 964.94 mm |
| 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 5a : -28.9°C to -26.1°C |
| Plant Hardiness Zone - 2012 | Zone 5a : -28.9°C to -26.1°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |