Pomeroy, Iowa has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 37 °F (low) to 57.3 °F (high). Annual precipitation averages 33.4 Inches. Pomeroy 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 | 8.7 °F | 26.2 °F | 0.83 in. |
| February | 12.8 °F | 30.5 °F | 1.02 in. |
| March | 24.8 °F | 44.3 °F | 1.93 in. |
| April | 35.9 °F | 58.8 °F | 3.59 in. |
| May | 48.5 °F | 70.0 °F | 4.72 in. |
| June | 59.5 °F | 80.2 °F | 5.15 in. |
| July | 62.9 °F | 83.2 °F | 3.74 in. |
| August | 60.1 °F | 80.7 °F | 4.31 in. |
| September | 51.1 °F | 75.0 °F | 2.98 in. |
| October | 38.7 °F | 61.9 °F | 2.4 in. |
| November | 25.9 °F | 45.2 °F | 1.52 in. |
| December | 14.9 °F | 31.4 °F | 1.24 in. |
| Annual | 37 °F | 57.3 °F | 33.43 in. |
| 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 : -20°F to -15°F |
| Plant Hardiness Zone - 2012 | Zone 5a : -20°F to -15°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |