Marcus, Iowa has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 2.6 °C (low) to 14 °C (high). Annual precipitation averages 778.8 Millimeters. Marcus 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. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -13.1 °C | -3.2 °C | 18.03 mm |
| February | -10.8 °C | -0.7 °C | 21.84 mm |
| March | -4.4 °C | 6.6 °C | 43.94 mm |
| April | 1.8 °C | 14.6 °C | 83.06 mm |
| May | 9.1 °C | 21.2 °C | 104.14 mm |
| June | 15.1 °C | 26.7 °C | 119.38 mm |
| July | 17.1 °C | 28.4 °C | 88.9 mm |
| August | 15.7 °C | 27.1 °C | 97.79 mm |
| September | 10.7 °C | 23.8 °C | 81.79 mm |
| October | 3.6 °C | 16.3 °C | 59.94 mm |
| November | -3.7 °C | 7.1 °C | 35.05 mm |
| December | -9.8 °C | -0.4 °C | 24.89 mm |
| Annual | 2.6 °C | 14 °C | 778.75 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 5a : -28.9°C to -26.1°C |
| Plant Hardiness Zone - 2012 | Zone 4b : -31.7°C to -28.9°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |