Longview, Washington has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 6.5 °C (low) to 16.3 °C (high). Annual precipitation averages 1173.5 Millimeters. Longview 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 Nov. 1 - Nov. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 2.1 °C | 8.2 °C | 165.1 mm |
| February | 1.7 °C | 10.2 °C | 115.57 mm |
| March | 3.3 °C | 12.6 °C | 121.92 mm |
| April | 5 °C | 15.3 °C | 101.85 mm |
| May | 8 °C | 18.9 °C | 69.85 mm |
| June | 10.3 °C | 21.3 °C | 50.55 mm |
| July | 12.3 °C | 24.8 °C | 13.72 mm |
| August | 12.3 °C | 25.6 °C | 20.32 mm |
| September | 10.1 °C | 23.1 °C | 47.5 mm |
| October | 6.8 °C | 16.9 °C | 111 mm |
| November | 3.9 °C | 11.2 °C | 176.78 mm |
| December | 1.9 °C | 7.7 °C | 179.32 mm |
| Annual | 6.5 °C | 16.3 °C | 1173.48 mm |
| Average First Frost Date | Nov. 1 - Nov. 10 |
| 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 8b : -9.4°C to -6.7°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Csb - Warm-Summer Mediterranean Climate |