Oldtown, Maryland has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 5.4 °C (low) to 18.6 °C (high). Annual precipitation averages 950 Millimeters. Oldtown is located in USDA Plant Hardiness Zone 7a. 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 | -5.5 °C | 5 °C | 70.61 mm |
| February | -4.7 °C | 7.2 °C | 58.67 mm |
| March | -0.8 °C | 12.2 °C | 86.61 mm |
| April | 4.1 °C | 19.3 °C | 79.5 mm |
| May | 9.7 °C | 24.2 °C | 89.92 mm |
| June | 14.7 °C | 28.5 °C | 96.27 mm |
| July | 17.1 °C | 31.1 °C | 78.74 mm |
| August | 16.4 °C | 30.1 °C | 82.8 mm |
| September | 12.2 °C | 26.4 °C | 98.81 mm |
| October | 5.1 °C | 19.9 °C | 66.8 mm |
| November | -0.1 °C | 12.9 °C | 65.28 mm |
| December | -3.1 °C | 6.9 °C | 75.95 mm |
| Annual | 5.4 °C | 18.6 °C | 949.96 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 7a : -17.8°C to -15°C |
| Plant Hardiness Zone - 2012 | Zone 6b : -20.6°C to -17.8°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |