Oldtown, Idaho has a Humid Continental Climate - Dry Cool Summer climate (Köppen classification: Dsb). Average annual temperatures range from 1.3 °C (low) to 14.3 °C (high). Annual precipitation averages 675.6 Millimeters. Oldtown is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around May 11 - May 20 through the first frost around Sep.11 - Sep. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -5.3 °C | 0.9 °C | 79.76 mm |
| February | -5.1 °C | 3.9 °C | 56.9 mm |
| March | -2.8 °C | 8.8 °C | 71.88 mm |
| April | 0.1 °C | 13.9 °C | 57.66 mm |
| May | 4.4 °C | 19.9 °C | 56.39 mm |
| June | 7.5 °C | 23.2 °C | 54.1 mm |
| July | 9.8 °C | 28.9 °C | 25.15 mm |
| August | 9 °C | 28.9 °C | 16 mm |
| September | 4.9 °C | 22.9 °C | 24.89 mm |
| October | 0.8 °C | 13.8 °C | 54.86 mm |
| November | -2.2 °C | 5.4 °C | 83.82 mm |
| December | -5.3 °C | 0.7 °C | 94.23 mm |
| Annual | 1.3 °C | 14.3 °C | 675.64 mm |
| Average First Frost Date | Sep.11 - Sep. 20 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 6a : -23.3°C to -20.6°C |
| Plant Hardiness Zone - 2012 | Zone 6a : -23.3°C to -20.6°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dsb - Humid Continental Climate - Dry Cool Summer |