Johnsonburg, New Jersey has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 4.5 °C (low) to 16 °C (high). Annual precipitation averages 1239.8 Millimeters. Johnsonburg is located in USDA Plant Hardiness Zone 6b. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -7.7 °C | 2.3 °C | 88.14 mm |
| February | -6.9 °C | 4.1 °C | 70.61 mm |
| March | -2.7 °C | 8.7 °C | 100.08 mm |
| April | 3.4 °C | 15.8 °C | 95 mm |
| May | 9 °C | 21.4 °C | 101.85 mm |
| June | 14.1 °C | 26 °C | 125.98 mm |
| July | 16.7 °C | 28.6 °C | 112.78 mm |
| August | 15.8 °C | 27.6 °C | 121.41 mm |
| September | 11.7 °C | 23.9 °C | 118.11 mm |
| October | 5.2 °C | 17.4 °C | 115.32 mm |
| November | -0.3 °C | 11.2 °C | 86.11 mm |
| December | -4.3 °C | 5.3 °C | 104.39 mm |
| Annual | 4.5 °C | 16 °C | 1239.78 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 6b : -20.6°C to -17.8°C |
| Plant Hardiness Zone - 2012 | Zone 6a : -23.3°C to -20.6°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |