Pioneer Junction, Montana has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 33.1 °F (low) to 58.2 °F (high). Annual precipitation averages 18.1 Inches. Pioneer Junction is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 20.2 °F | 33.1 °F | 1.87 in. |
| February | 20.6 °F | 39.3 °F | 1.26 in. |
| March | 25.6 °F | 48.7 °F | 1.78 in. |
| April | 30.8 °F | 58.4 °F | 1.08 in. |
| May | 38.1 °F | 68.6 °F | 1.53 in. |
| June | 44.7 °F | 75.2 °F | 1.81 in. |
| July | 48.4 °F | 85.9 °F | 0.87 in. |
| August | 47.1 °F | 86.0 °F | 0.69 in. |
| September | 40.2 °F | 74.2 °F | 0.99 in. |
| October | 33.0 °F | 56.5 °F | 1.68 in. |
| November | 27.0 °F | 40.3 °F | 2.3 in. |
| December | 21.1 °F | 32.1 °F | 2.23 in. |
| Annual | 33.1 °F | 58.2 °F | 18.09 in. |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 6a : -10°F to -5°F |
| Plant Hardiness Zone - 2012 | Zone 5b : -15°F to -10°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |