Bath, Maine has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 36.4 °F (low) to 55.2 °F (high). Annual precipitation averages 50 Inches. Bath is located in USDA Plant Hardiness Zone 5b. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 11.9 °F | 30.8 °F | 3.89 in. |
| February | 14.0 °F | 33.7 °F | 3.67 in. |
| March | 23.4 °F | 41.0 °F | 4.42 in. |
| April | 33.3 °F | 52.6 °F | 4.41 in. |
| May | 43.6 °F | 63.4 °F | 3.64 in. |
| June | 52.9 °F | 72.1 °F | 4.65 in. |
| July | 59.0 °F | 78.3 °F | 3.53 in. |
| August | 57.9 °F | 77.6 °F | 3.18 in. |
| September | 50.7 °F | 70.4 °F | 3.95 in. |
| October | 39.9 °F | 58.4 °F | 5.33 in. |
| November | 30.3 °F | 47.2 °F | 4.59 in. |
| December | 19.8 °F | 36.9 °F | 4.74 in. |
| Annual | 36.4 °F | 55.2 °F | 50 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 5b : -15°F to -10°F |
| Plant Hardiness Zone - 2012 | Zone 5b : -15°F to -10°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |