Altona, Indiana has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 4.5 °C (low) to 15.5 °C (high). Annual precipitation averages 984.8 Millimeters. Altona is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -8.2 °C | 0.1 °C | 62.99 mm |
| February | -7.2 °C | 2.2 °C | 53.09 mm |
| March | -2.6 °C | 8.3 °C | 63.25 mm |
| April | 3.2 °C | 15.8 °C | 93.98 mm |
| May | 9.5 °C | 22 °C | 116.33 mm |
| June | 14.9 °C | 26.9 °C | 103.89 mm |
| July | 16.7 °C | 28.8 °C | 96.01 mm |
| August | 15.6 °C | 27.7 °C | 99.06 mm |
| September | 11.4 °C | 24.6 °C | 80.26 mm |
| October | 5.4 °C | 17.5 °C | 76.71 mm |
| November | -0.2 °C | 9.4 °C | 76.71 mm |
| December | -5 °C | 2.8 °C | 62.48 mm |
| Annual | 4.5 °C | 15.5 °C | 984.76 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 6a : -23.3°C to -20.6°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 |