Hazleton, Iowa has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 36.5 °F (low) to 56.8 °F (high). Annual precipitation averages 37.2 Inches. Hazleton is located in USDA Plant Hardiness Zone 5a. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 8.5 °F | 25.9 °F | 1.15 in. |
| February | 12.5 °F | 30.1 °F | 1.19 in. |
| March | 24.3 °F | 43.4 °F | 1.9 in. |
| April | 35.7 °F | 58.0 °F | 3.66 in. |
| May | 47.8 °F | 69.8 °F | 4.59 in. |
| June | 58.5 °F | 79.5 °F | 5.65 in. |
| July | 61.6 °F | 82.3 °F | 4.93 in. |
| August | 59.0 °F | 80.4 °F | 4.22 in. |
| September | 50.5 °F | 74.4 °F | 3.73 in. |
| October | 38.2 °F | 61.2 °F | 2.74 in. |
| November | 26.1 °F | 44.9 °F | 1.85 in. |
| December | 15.2 °F | 31.6 °F | 1.57 in. |
| Annual | 36.5 °F | 56.8 °F | 37.18 in. |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 1 - May 10 |
| 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 | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |