Tenino, Washington has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 41.8 °F (low) to 61.1 °F (high). Annual precipitation averages 55.3 Inches. Tenino is located in USDA Plant Hardiness Zone 8b. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 34.5 °F | 46.6 °F | 7.92 in. |
| February | 34.0 °F | 49.7 °F | 5.46 in. |
| March | 36.1 °F | 54.1 °F | 5.87 in. |
| April | 38.8 °F | 59.2 °F | 4.45 in. |
| May | 44.3 °F | 66.1 °F | 2.7 in. |
| June | 48.7 °F | 70.8 °F | 1.95 in. |
| July | 52.1 °F | 77.6 °F | 0.7 in. |
| August | 52.1 °F | 78.5 °F | 1.07 in. |
| September | 47.9 °F | 72.7 °F | 2.01 in. |
| October | 42.2 °F | 61.2 °F | 5.26 in. |
| November | 37.1 °F | 51.3 °F | 9.4 in. |
| December | 34.0 °F | 45.5 °F | 8.5 in. |
| Annual | 41.8 °F | 61.1 °F | 55.29 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 50-75 Days |
| Plant Hardiness Zone | Zone 8b : 15°F to 20°F |
| Plant Hardiness Zone - 2012 | Zone 8a : 10°F to 15°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Csb - Warm-Summer Mediterranean Climate |