Lander, Wyoming has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from -0.9 °C (low) to 15 °C (high). Annual precipitation averages 321.3 Millimeters. Lander is located in USDA Plant Hardiness Zone 5a. The growing season typically runs from the last frost around May 11 - May 20 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -13.3 °C | 0.8 °C | 12.45 mm |
| February | -11.3 °C | 3.3 °C | 17.53 mm |
| March | -5.5 °C | 9.6 °C | 26.16 mm |
| April | -1.4 °C | 13.9 °C | 47.75 mm |
| May | 3.8 °C | 19 °C | 66.55 mm |
| June | 8.1 °C | 25.4 °C | 27.43 mm |
| July | 12 °C | 30.8 °C | 15.75 mm |
| August | 10.9 °C | 29.8 °C | 16.26 mm |
| September | 6.1 °C | 23.9 °C | 28.96 mm |
| October | -0.4 °C | 15.6 °C | 34.29 mm |
| November | -7.3 °C | 7.3 °C | 14.99 mm |
| December | -12.5 °C | 1 °C | 13.21 mm |
| Annual | -0.9 °C | 15 °C | 321.33 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | Over 180 Days |
| Plant Hardiness Zone | Zone 5a : -28.9°C to -26.1°C |
| Plant Hardiness Zone - 2012 | Zone 4b : -31.7°C to -28.9°C |
| Current Drought Conditions | Extreme Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |