Bartlett, Iowa has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 4.3 °C (low) to 17 °C (high). Annual precipitation averages 845.6 Millimeters. Bartlett is located in USDA Plant Hardiness Zone 5b. The growing season typically runs from the last frost around Apr. 11 - Apr. 20 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -10.8 °C | 0.6 °C | 20.07 mm |
| February | -8.5 °C | 3.7 °C | 25.91 mm |
| March | -2.3 °C | 10.9 °C | 45.21 mm |
| April | 3.6 °C | 17.6 °C | 85.09 mm |
| May | 10.6 °C | 23.3 °C | 137.92 mm |
| June | 16.5 °C | 28.6 °C | 129.79 mm |
| July | 18.7 °C | 30.3 °C | 98.04 mm |
| August | 17.2 °C | 29.6 °C | 90.17 mm |
| September | 11.8 °C | 26.1 °C | 78.99 mm |
| October | 4.7 °C | 19.2 °C | 65.53 mm |
| November | -2.4 °C | 10.3 °C | 39.12 mm |
| December | -7.9 °C | 3.3 °C | 29.72 mm |
| Annual | 4.3 °C | 17 °C | 845.56 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 5b : -26.1°C to -23.3°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 |