Arlington Heights, Washington has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 42 °F (low) to 59.5 °F (high). Annual precipitation averages 49.5 Inches. Arlington Heights is located in USDA Plant Hardiness Zone 8b. The growing season typically runs from the last frost around Apr. 1 - Apr. 10 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 33.3 °F | 45.4 °F | 6.19 in. |
| February | 33.2 °F | 48.3 °F | 4.55 in. |
| March | 35.8 °F | 52.4 °F | 5.43 in. |
| April | 40.0 °F | 58.2 °F | 4.18 in. |
| May | 45.5 °F | 64.8 °F | 3.15 in. |
| June | 49.6 °F | 68.6 °F | 2.57 in. |
| July | 53.0 °F | 75.1 °F | 1.18 in. |
| August | 53.2 °F | 76.0 °F | 1.24 in. |
| September | 48.8 °F | 70.6 °F | 2.54 in. |
| October | 42.2 °F | 59.7 °F | 5.31 in. |
| November | 36.7 °F | 50.1 °F | 6.67 in. |
| December | 33.1 °F | 44.4 °F | 6.48 in. |
| Annual | 42 °F | 59.5 °F | 49.49 in. |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 1 - Apr. 10 |
| Average Days With Frost | 40-50 Days |
| Plant Hardiness Zone | Zone 8b : 15°F to 20°F |
| Plant Hardiness Zone - 2012 | Zone 8b : 15°F to 20°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Csb - Warm-Summer Mediterranean Climate |