Altoona, Washington has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 44.5 °F (low) to 59.4 °F (high). Annual precipitation averages 99.8 Inches. Altoona is located in USDA Plant Hardiness Zone 9a. 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 | 37.6 °F | 47.9 °F | 15.83 in. |
| February | 37.6 °F | 50.7 °F | 9.85 in. |
| March | 38.6 °F | 53.8 °F | 11.2 in. |
| April | 41.2 °F | 57.4 °F | 7.81 in. |
| May | 45.9 °F | 62.2 °F | 4.25 in. |
| June | 49.5 °F | 65.9 °F | 3.4 in. |
| July | 53.5 °F | 70.5 °F | 1.07 in. |
| August | 53.6 °F | 72.2 °F | 1.7 in. |
| September | 51.6 °F | 70.3 °F | 3.83 in. |
| October | 46.3 °F | 61.6 °F | 9.6 in. |
| November | 41.2 °F | 52.8 °F | 15.25 in. |
| December | 37.2 °F | 47.3 °F | 15.99 in. |
| Annual | 44.5 °F | 59.4 °F | 99.78 in. |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 40-50 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 | Normal |
| Köppen Climate Classification | Csb - Warm-Summer Mediterranean Climate |