Rochester, Washington has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 41.8 °F (low) to 61.3 °F (high). Annual precipitation averages 57 Inches. Rochester is located in USDA Plant Hardiness Zone 8b. The growing season typically runs from the last frost around Apr. 11 - Apr. 20 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 34.7 °F | 46.9 °F | 8.13 in. |
| February | 34.2 °F | 50.1 °F | 5.54 in. |
| March | 36.0 °F | 54.6 °F | 6.23 in. |
| April | 38.7 °F | 59.5 °F | 4.27 in. |
| May | 44.1 °F | 66.5 °F | 2.59 in. |
| June | 48.4 °F | 70.8 °F | 1.84 in. |
| July | 51.9 °F | 77.4 °F | 0.61 in. |
| August | 51.9 °F | 78.2 °F | 1.02 in. |
| September | 47.8 °F | 72.8 °F | 2.02 in. |
| October | 42.1 °F | 61.2 °F | 5.83 in. |
| November | 37.1 °F | 51.7 °F | 10.1 in. |
| December | 34.3 °F | 45.9 °F | 8.83 in. |
| Annual | 41.8 °F | 61.3 °F | 57.01 in. |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 50-75 Days |
| Plant Hardiness Zone | Zone 8b : 15°F to 20°F |
| Plant Hardiness Zone - 2012 | Zone 8a : 10°F to 15°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Csb - Warm-Summer Mediterranean Climate |