Deep River, Iowa has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 38.9 °F (low) to 59 °F (high). Annual precipitation averages 37.4 Inches. Deep River is located in USDA Plant Hardiness Zone 5b. 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 | 11.8 °F | 28.6 °F | 1.12 in. |
| February | 15.4 °F | 33.4 °F | 1.38 in. |
| March | 26.4 °F | 46.6 °F | 2.14 in. |
| April | 37.6 °F | 60.1 °F | 3.72 in. |
| May | 50.2 °F | 71.2 °F | 4.88 in. |
| June | 60.9 °F | 81.1 °F | 5.38 in. |
| July | 64.0 °F | 84.5 °F | 4.31 in. |
| August | 61.4 °F | 82.6 °F | 4.37 in. |
| September | 52.4 °F | 75.9 °F | 3.56 in. |
| October | 40.3 °F | 62.9 °F | 2.85 in. |
| November | 28.3 °F | 47.2 °F | 2.14 in. |
| December | 18.0 °F | 34.3 °F | 1.54 in. |
| Annual | 38.9 °F | 59 °F | 37.39 in. |
| 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 5b : -15°F to -10°F |
| Plant Hardiness Zone - 2012 | Zone 5a : -20°F to -15°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |