Key Center, Washington has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 6.2 °C (low) to 16 °C (high). Annual precipitation averages 1320.5 Millimeters. Key Center is located in USDA Plant Hardiness Zone 8b. The growing season typically runs from the last frost around Mar. 21 - Mar. 31 through the first frost around Nov. 1 - Nov. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 1.8 °C | 8.2 °C | 202.18 mm |
| February | 1.6 °C | 9.7 °C | 127 mm |
| March | 2.8 °C | 12.1 °C | 146.3 mm |
| April | 4.5 °C | 15.3 °C | 100.84 mm |
| May | 7.6 °C | 19.1 °C | 58.93 mm |
| June | 10.1 °C | 21.6 °C | 40.13 mm |
| July | 12 °C | 25 °C | 16.51 mm |
| August | 12.1 °C | 25.1 °C | 29.46 mm |
| September | 9.8 °C | 21.9 °C | 45.21 mm |
| October | 6.5 °C | 15.3 °C | 127 mm |
| November | 3.4 °C | 10.7 °C | 218.19 mm |
| December | 1.6 °C | 7.7 °C | 208.79 mm |
| Annual | 6.2 °C | 16 °C | 1320.54 mm |
| Average First Frost Date | Nov. 1 - Nov. 10 |
| Average Last Frost Date | Mar. 21 - Mar. 31 |
| Average Days With Frost | 40-50 Days |
| Plant Hardiness Zone | Zone 8b : -9.4°C to -6.7°C |
| Plant Hardiness Zone - 2012 | Zone 8b : -9.4°C to -6.7°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Csb - Warm-Summer Mediterranean Climate |