Sammamish, Washington has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 44.9 °F (low) to 61.1 °F (high). Annual precipitation averages 43.6 Inches. Sammamish is located in USDA Plant Hardiness Zone 9a. The growing season typically runs from the last frost around Mar. 11 - Mar. 20 through the first frost around Nov. 11 - Nov. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 36.3 °F | 47.4 °F | 5.71 in. |
| February | 36.4 °F | 50.1 °F | 4.23 in. |
| March | 38.9 °F | 54.0 °F | 4.61 in. |
| April | 42.4 °F | 59.3 °F | 3.69 in. |
| May | 47.7 °F | 66.1 °F | 2.4 in. |
| June | 52.1 °F | 70.2 °F | 2.18 in. |
| July | 55.5 °F | 76.8 °F | 0.85 in. |
| August | 55.6 °F | 77.5 °F | 1.04 in. |
| September | 51.9 °F | 71.8 °F | 1.94 in. |
| October | 45.7 °F | 61.0 °F | 4.48 in. |
| November | 40.0 °F | 51.9 °F | 6.45 in. |
| December | 36.1 °F | 46.5 °F | 6.04 in. |
| Annual | 44.9 °F | 61.1 °F | 43.62 in. |
| Average First Frost Date | Nov. 11 - Nov. 20 |
| Average Last Frost Date | Mar. 11 - Mar. 20 |
| Average Days With Frost | 30-40 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 |