Tualatin, Oregon has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 44.6 °F (low) to 63.5 °F (high). Annual precipitation averages 43.2 Inches. Tualatin is located in USDA Plant Hardiness Zone 9a. The growing season typically runs from the last frost around Mar. 1 - Mar. 10 through the first frost around Nov. 21 - Nov. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 36.1 °F | 47.4 °F | 6.43 in. |
| February | 36.4 °F | 51.2 °F | 4.94 in. |
| March | 38.7 °F | 56.0 °F | 4.56 in. |
| April | 42.0 °F | 61.3 °F | 3.36 in. |
| May | 47.4 °F | 68.4 °F | 2.36 in. |
| June | 51.7 °F | 73.6 °F | 1.81 in. |
| July | 55.6 °F | 81.6 °F | 0.32 in. |
| August | 55.5 °F | 82.1 °F | 0.41 in. |
| September | 51.3 °F | 76.2 °F | 1.45 in. |
| October | 45.0 °F | 64.1 °F | 3.83 in. |
| November | 39.7 °F | 53.0 °F | 6.42 in. |
| December | 35.7 °F | 46.5 °F | 7.3 in. |
| Annual | 44.6 °F | 63.5 °F | 43.19 in. |
| Average First Frost Date | Nov. 21 - Nov. 30 |
| Average Last Frost Date | Mar. 1 - Mar. 10 |
| Average Days With Frost | 20-30 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 | Abnormally Dry |
| Köppen Climate Classification | Csb - Warm-Summer Mediterranean Climate |