Manchester, Washington has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 7.4 °C (low) to 16.1 °C (high). Annual precipitation averages 1114.1 Millimeters. Manchester is located in USDA Plant Hardiness Zone 9a. The growing season typically runs from the last frost around Mar. 21 - Mar. 31 through the first frost around Nov. 11 - Nov. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 2.9 °C | 8.6 °C | 186.44 mm |
| February | 2.9 °C | 10 °C | 97.03 mm |
| March | 4.2 °C | 12.3 °C | 120.9 mm |
| April | 5.8 °C | 15.1 °C | 75.69 mm |
| May | 8.7 °C | 18.8 °C | 49.28 mm |
| June | 11.2 °C | 21.1 °C | 41.15 mm |
| July | 13 °C | 24.6 °C | 22.86 mm |
| August | 13.2 °C | 25 °C | 24.64 mm |
| September | 11.3 °C | 21.9 °C | 41.66 mm |
| October | 8.1 °C | 15.9 °C | 107.95 mm |
| November | 4.8 °C | 11.1 °C | 167.64 mm |
| December | 2.8 °C | 8.2 °C | 178.82 mm |
| Annual | 7.4 °C | 16.1 °C | 1114.06 mm |
| Average First Frost Date | Nov. 11 - Nov. 20 |
| Average Last Frost Date | Mar. 21 - Mar. 31 |
| Average Days With Frost | 30-40 Days |
| Plant Hardiness Zone | Zone 9a : -6.7°C to -3.9°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 |