Riddle, Oregon has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 43.1 °F (low) to 67.3 °F (high). Annual precipitation averages 32 Inches. Riddle is located in USDA Plant Hardiness Zone 9a. The growing season typically runs from the last frost around Apr. 1 - Apr. 10 through the first frost around Nov. 1 - Nov. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 35.4 °F | 50.1 °F | 4.95 in. |
| February | 36.0 °F | 54.8 °F | 3.54 in. |
| March | 37.5 °F | 59.3 °F | 3.5 in. |
| April | 40.3 °F | 64.6 °F | 2.63 in. |
| May | 45.3 °F | 71.7 °F | 1.91 in. |
| June | 49.8 °F | 78.0 °F | 0.94 in. |
| July | 54.4 °F | 86.9 °F | 0.24 in. |
| August | 53.3 °F | 87.2 °F | 0.29 in. |
| September | 48.1 °F | 82.0 °F | 0.73 in. |
| October | 42.3 °F | 69.7 °F | 2.23 in. |
| November | 39.3 °F | 55.5 °F | 4.65 in. |
| December | 35.3 °F | 48.3 °F | 6.36 in. |
| Annual | 43.1 °F | 67.3 °F | 31.97 in. |
| Average First Frost Date | Nov. 1 - Nov. 10 |
| Average Last Frost Date | Apr. 1 - Apr. 10 |
| 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 | Severe Drought |
| Köppen Climate Classification | Csb - Warm-Summer Mediterranean Climate |