Timonium, Maryland has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 45.6 °F (low) to 65.4 °F (high). Annual precipitation averages 48.7 Inches. Timonium is located in USDA Plant Hardiness Zone 7b. The growing season typically runs from the last frost around Apr. 11 - Apr. 20 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 24.8 °F | 42.2 °F | 3.45 in. |
| February | 26.3 °F | 45.0 °F | 2.94 in. |
| March | 33.0 °F | 53.4 °F | 4.31 in. |
| April | 43.5 °F | 65.4 °F | 3.81 in. |
| May | 53.2 °F | 74.5 °F | 4.31 in. |
| June | 62.3 °F | 83.0 °F | 4.3 in. |
| July | 67.3 °F | 87.4 °F | 4.5 in. |
| August | 65.4 °F | 85.6 °F | 4.2 in. |
| September | 58.7 °F | 78.8 °F | 4.78 in. |
| October | 46.9 °F | 67.4 °F | 4.49 in. |
| November | 36.6 °F | 56.2 °F | 3.46 in. |
| December | 29.5 °F | 46.2 °F | 4.12 in. |
| Annual | 45.6 °F | 65.4 °F | 48.67 in. |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 75-100 Days |
| Plant Hardiness Zone | Zone 7b : 5°F to 10°F |
| Plant Hardiness Zone - 2012 | Zone 7a : 0°F to 5°F |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |