Parker, Idaho has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from -1.3 °C (low) to 13.3 °C (high). Annual precipitation averages 343.9 Millimeters. Parker is located in USDA Plant Hardiness Zone 5a. The growing season typically runs from the last frost around May 21 - May 31 through the first frost around Sep.1 - Sep. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -12.1 °C | -2.1 °C | 31.24 mm |
| February | -10.3 °C | 0.4 °C | 20.07 mm |
| March | -5.3 °C | 7.1 °C | 24.13 mm |
| April | -1.4 °C | 13.3 °C | 30.48 mm |
| May | 3 °C | 18.5 °C | 48.77 mm |
| June | 6.6 °C | 23.2 °C | 41.66 mm |
| July | 9.4 °C | 28.8 °C | 13.97 mm |
| August | 8.4 °C | 28.6 °C | 16.51 mm |
| September | 4.3 °C | 22.8 °C | 25.15 mm |
| October | -1.1 °C | 14.6 °C | 31.75 mm |
| November | -6.2 °C | 5.5 °C | 27.18 mm |
| December | -11.1 °C | -1.4 °C | 33.02 mm |
| Annual | -1.3 °C | 13.3 °C | 343.93 mm |
| Average First Frost Date | Sep.1 - Sep. 10 |
| Average Last Frost Date | May 21 - May 31 |
| Average Days With Frost | Over 180 Days |
| Plant Hardiness Zone | Zone 5a : -28.9°C to -26.1°C |
| Plant Hardiness Zone - 2012 | Zone 4b : -31.7°C to -28.9°C |
| Current Drought Conditions | Extreme Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |