Lester, Iowa has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 35.2 °F (low) to 56.7 °F (high). Annual precipitation averages 29 Inches. Lester 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 | 6.8 °F | 25.4 °F | 0.64 in. |
| February | 11.1 °F | 30.2 °F | 0.81 in. |
| March | 22.6 °F | 42.9 °F | 1.5 in. |
| April | 34.1 °F | 57.5 °F | 2.96 in. |
| May | 46.8 °F | 69.7 °F | 3.79 in. |
| June | 58.3 °F | 80.0 °F | 4.74 in. |
| July | 61.6 °F | 83.7 °F | 3.4 in. |
| August | 58.9 °F | 81.4 °F | 3.32 in. |
| September | 49.8 °F | 74.7 °F | 3.17 in. |
| October | 36.7 °F | 60.7 °F | 2.34 in. |
| November | 23.6 °F | 44.0 °F | 1.4 in. |
| December | 12.4 °F | 30.0 °F | 0.94 in. |
| Annual | 35.2 °F | 56.7 °F | 29.01 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 4b : -25°F to -20°F |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |