Swanton, Maryland has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 38.8 °F (low) to 57.9 °F (high). Annual precipitation averages 50.9 Inches. Swanton 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 Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 18.5 °F | 34.3 °F | 4.21 in. |
| February | 20.3 °F | 37.9 °F | 3.93 in. |
| March | 26.6 °F | 46.1 °F | 4.47 in. |
| April | 36.6 °F | 59.2 °F | 4.57 in. |
| May | 46.7 °F | 67.7 °F | 5.19 in. |
| June | 55.1 °F | 74.9 °F | 5.3 in. |
| July | 58.8 °F | 78.5 °F | 4.61 in. |
| August | 57.6 °F | 77.4 °F | 3.9 in. |
| September | 50.9 °F | 71.6 °F | 3.76 in. |
| October | 40.2 °F | 60.4 °F | 3.36 in. |
| November | 30.6 °F | 48.3 °F | 3.48 in. |
| December | 23.3 °F | 38.5 °F | 4.12 in. |
| Annual | 38.8 °F | 57.9 °F | 50.9 in. |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 6a : -10°F to -5°F |
| Plant Hardiness Zone - 2012 | Zone 6a : -10°F to -5°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |