Middleton, Idaho has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from 4 °C (low) to 18.2 °C (high). Annual precipitation averages 295.7 Millimeters. Middleton is located in USDA Plant Hardiness Zone 7a. 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 | -4.5 °C | 3.4 °C | 38.1 mm |
| February | -2.8 °C | 7.9 °C | 25.15 mm |
| March | 0.1 °C | 13.7 °C | 32.77 mm |
| April | 2.8 °C | 17.7 °C | 30.73 mm |
| May | 7.3 °C | 22.8 °C | 33.53 mm |
| June | 11.1 °C | 27.6 °C | 17.53 mm |
| July | 14.7 °C | 33.5 °C | 6.35 mm |
| August | 13.5 °C | 32.7 °C | 4.06 mm |
| September | 8.7 °C | 27 °C | 14.48 mm |
| October | 2.9 °C | 18.9 °C | 19.81 mm |
| November | -1.7 °C | 9.8 °C | 29.72 mm |
| December | -4.4 °C | 3.9 °C | 43.43 mm |
| Annual | 4 °C | 18.2 °C | 295.66 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 7a : -17.8°C to -15°C |
| Plant Hardiness Zone - 2012 | Zone 7a : -17.8°C to -15°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |