Primghar, Iowa has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 35.8 °F (low) to 56.3 °F (high). Annual precipitation averages 31.1 Inches. Primghar 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 | 7.1 °F | 24.9 °F | 0.78 in. |
| February | 11.4 °F | 29.4 °F | 0.9 in. |
| March | 22.9 °F | 42.5 °F | 1.7 in. |
| April | 34.6 °F | 57.6 °F | 3.3 in. |
| May | 47.5 °F | 69.8 °F | 4.19 in. |
| June | 58.5 °F | 79.6 °F | 4.82 in. |
| July | 62.1 °F | 83.1 °F | 3.62 in. |
| August | 59.7 °F | 80.5 °F | 3.72 in. |
| September | 50.9 °F | 74.3 °F | 3.23 in. |
| October | 38.0 °F | 60.9 °F | 2.33 in. |
| November | 24.4 °F | 43.8 °F | 1.47 in. |
| December | 13.0 °F | 29.7 °F | 1.02 in. |
| Annual | 35.8 °F | 56.3 °F | 31.08 in. |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 5a : -20°F to -15°F |
| Plant Hardiness Zone - 2012 | Zone 4b : -25°F to -20°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |