Rochester, Washington has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 5.4 °C (low) to 16.3 °C (high). Annual precipitation averages 1448.1 Millimeters. 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 | 1.5 °C | 8.3 °C | 206.5 mm |
| February | 1.2 °C | 10.1 °C | 140.72 mm |
| March | 2.2 °C | 12.6 °C | 158.24 mm |
| April | 3.7 °C | 15.3 °C | 108.46 mm |
| May | 6.7 °C | 19.2 °C | 65.79 mm |
| June | 9.1 °C | 21.6 °C | 46.74 mm |
| July | 11.1 °C | 25.2 °C | 15.49 mm |
| August | 11.1 °C | 25.7 °C | 25.91 mm |
| September | 8.8 °C | 22.7 °C | 51.31 mm |
| October | 5.6 °C | 16.2 °C | 148.08 mm |
| November | 2.8 °C | 10.9 °C | 256.54 mm |
| December | 1.3 °C | 7.7 °C | 224.28 mm |
| Annual | 5.4 °C | 16.3 °C | 1448.06 mm |
| 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 : -9.4°C to -6.7°C |
| Plant Hardiness Zone - 2012 | Zone 8a : -12.2°C to -9.4°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Csb - Warm-Summer Mediterranean Climate |