Martinsburg, Iowa has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 4.6 °C (low) to 15.8 °C (high). Annual precipitation averages 967.5 Millimeters. Martinsburg is located in USDA Plant Hardiness Zone 5b. The growing season typically runs from the last frost around Apr. 11 - Apr. 20 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -10.1 °C | -0.6 °C | 32.26 mm |
| February | -8.1 °C | 2.1 °C | 39.62 mm |
| March | -2.1 °C | 9.3 °C | 57.15 mm |
| April | 4 °C | 16.5 °C | 96.77 mm |
| May | 10.7 °C | 22.1 °C | 130.3 mm |
| June | 16.2 °C | 27.5 °C | 135.64 mm |
| July | 18.2 °C | 29.5 °C | 106.93 mm |
| August | 16.8 °C | 28.4 °C | 105.66 mm |
| September | 11.8 °C | 24.8 °C | 95.25 mm |
| October | 5.3 °C | 17.9 °C | 71.63 mm |
| November | -1.2 °C | 9.4 °C | 55.63 mm |
| December | -6.8 °C | 2.3 °C | 40.64 mm |
| Annual | 4.6 °C | 15.8 °C | 967.48 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 5b : -26.1°C to -23.3°C |
| Plant Hardiness Zone - 2012 | Zone 5b : -26.1°C to -23.3°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |