Rock River, Wyoming has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 28.9 °F (low) to 55.4 °F (high). Annual precipitation averages 14 Inches. Rock River is located in USDA Plant Hardiness Zone 4b. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Sep.1 - Sep. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 12.0 °F | 32.6 °F | 0.62 in. |
| February | 13.2 °F | 34.3 °F | 0.65 in. |
| March | 20.7 °F | 44.0 °F | 0.98 in. |
| April | 26.6 °F | 51.6 °F | 1.53 in. |
| May | 35.0 °F | 62.2 °F | 2.28 in. |
| June | 43.3 °F | 73.9 °F | 1.51 in. |
| July | 49.4 °F | 82.2 °F | 1.38 in. |
| August | 47.0 °F | 80.2 °F | 1.07 in. |
| September | 38.7 °F | 71.5 °F | 1.16 in. |
| October | 28.7 °F | 57.0 °F | 1.19 in. |
| November | 19.6 °F | 42.5 °F | 0.9 in. |
| December | 12.2 °F | 32.6 °F | 0.69 in. |
| Annual | 28.9 °F | 55.4 °F | 13.96 in. |
| Average First Frost Date | Sep.1 - Sep. 10 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | Over 180 Days |
| Plant Hardiness Zone | Zone 4b : -25°F to -20°F |
| Plant Hardiness Zone - 2012 | Zone 4b : -25°F to -20°F |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |