South Haven, Indiana has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 41.4 °F (low) to 59.8 °F (high). Annual precipitation averages 40.6 Inches. South Haven is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 17.8 °F | 32.5 °F | 2.46 in. |
| February | 20.4 °F | 36.4 °F | 2.18 in. |
| March | 28.8 °F | 47.0 °F | 2.38 in. |
| April | 38.8 °F | 59.4 °F | 3.66 in. |
| May | 49.4 °F | 70.4 °F | 4.13 in. |
| June | 59.3 °F | 79.7 °F | 4.62 in. |
| July | 63.9 °F | 83.1 °F | 4.3 in. |
| August | 62.4 °F | 81.6 °F | 4.22 in. |
| September | 54.9 °F | 76.0 °F | 3.51 in. |
| October | 43.7 °F | 63.8 °F | 3.98 in. |
| November | 33.4 °F | 49.7 °F | 2.84 in. |
| December | 23.7 °F | 37.6 °F | 2.31 in. |
| Annual | 41.4 °F | 59.8 °F | 40.59 in. |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 6a : -10°F to -5°F |
| Plant Hardiness Zone - 2012 | Zone 5b : -15°F to -10°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |