Delaware, Oklahoma has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 8.2 °C (low) to 21 °C (high). Annual precipitation averages 1080.3 Millimeters. Delaware is located in USDA Plant Hardiness Zone 7a. The growing season typically runs from the last frost around Apr. 1 - Apr. 10 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -4.6 °C | 7.9 °C | 40.89 mm |
| February | -2.7 °C | 10.4 °C | 44.96 mm |
| March | 2.3 °C | 15.8 °C | 78.49 mm |
| April | 7.6 °C | 20.9 °C | 115.82 mm |
| May | 13.6 °C | 25.2 °C | 169.16 mm |
| June | 18.8 °C | 30.1 °C | 132.08 mm |
| July | 21.1 °C | 33.1 °C | 95.76 mm |
| August | 19.9 °C | 32.9 °C | 92.96 mm |
| September | 15.3 °C | 28.8 °C | 97.28 mm |
| October | 8.3 °C | 22.3 °C | 91.44 mm |
| November | 2.2 °C | 15.6 °C | 66.55 mm |
| December | -2.9 °C | 9.2 °C | 54.86 mm |
| Annual | 8.2 °C | 21 °C | 1080.25 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 1 - Apr. 10 |
| Average Days With Frost | 75-100 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 | Normal |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |