Manchester, Washington has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 45.3 °F (low) to 60.9 °F (high). Annual precipitation averages 43.9 Inches. 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 | 37.3 °F | 47.5 °F | 7.34 in. |
| February | 37.3 °F | 50.0 °F | 3.82 in. |
| March | 39.5 °F | 54.1 °F | 4.76 in. |
| April | 42.5 °F | 59.2 °F | 2.98 in. |
| May | 47.7 °F | 65.8 °F | 1.94 in. |
| June | 52.1 °F | 69.9 °F | 1.62 in. |
| July | 55.4 °F | 76.2 °F | 0.9 in. |
| August | 55.7 °F | 77.0 °F | 0.97 in. |
| September | 52.3 °F | 71.4 °F | 1.64 in. |
| October | 46.5 °F | 60.7 °F | 4.25 in. |
| November | 40.7 °F | 52.0 °F | 6.6 in. |
| December | 37.0 °F | 46.7 °F | 7.04 in. |
| Annual | 45.3 °F | 60.9 °F | 43.86 in. |
| 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 : 20°F to 25°F |
| Plant Hardiness Zone - 2012 | Zone 8b : 15°F to 20°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Csb - Warm-Summer Mediterranean Climate |