Longtown, Oklahoma has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 10.3 °C (low) to 22.6 °C (high). Annual precipitation averages 1164.9 Millimeters. Longtown is located in USDA Plant Hardiness Zone 7b. The growing season typically runs from the last frost around Mar. 21 - Mar. 31 through the first frost around Nov. 1 - Nov. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -2 °C | 10.1 °C | 61.98 mm |
| February | 0.1 °C | 12.5 °C | 58.17 mm |
| March | 4.9 °C | 17.5 °C | 95.25 mm |
| April | 9.5 °C | 22.4 °C | 111.51 mm |
| May | 15.2 °C | 26.4 °C | 148.84 mm |
| June | 20.1 °C | 31.2 °C | 127.25 mm |
| July | 22.1 °C | 34.1 °C | 92.71 mm |
| August | 21.4 °C | 34.1 °C | 82.55 mm |
| September | 17 °C | 29.9 °C | 117.35 mm |
| October | 10.6 °C | 23.8 °C | 106.43 mm |
| November | 4.8 °C | 17.3 °C | 89.66 mm |
| December | -0.3 °C | 11.4 °C | 73.15 mm |
| Annual | 10.3 °C | 22.6 °C | 1164.85 mm |
| Average First Frost Date | Nov. 1 - Nov. 10 |
| Average Last Frost Date | Mar. 21 - Mar. 31 |
| Average Days With Frost | 50-75 Days |
| Plant Hardiness Zone | Zone 7b : -15°C to -12.2°C |
| Plant Hardiness Zone - 2012 | Zone 7b : -15°C to -12.2°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |