Cairo, Missouri has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 6.6 °C (low) to 17.7 °C (high). Annual precipitation averages 1076.2 Millimeters. Cairo is located in USDA Plant Hardiness Zone 6b. 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 | -7.3 °C | 2.5 °C | 45.97 mm |
| February | -5.3 °C | 5.4 °C | 51.82 mm |
| March | 0.3 °C | 11.9 °C | 76.45 mm |
| April | 6.3 °C | 18.3 °C | 114.05 mm |
| May | 12.1 °C | 23.3 °C | 133.35 mm |
| June | 17.3 °C | 28.2 °C | 133.6 mm |
| July | 19.4 °C | 30.6 °C | 118.36 mm |
| August | 18.2 °C | 29.9 °C | 98.81 mm |
| September | 13.4 °C | 25.8 °C | 100.58 mm |
| October | 7.3 °C | 19.6 °C | 83.82 mm |
| November | 1.3 °C | 11.8 °C | 67.31 mm |
| December | -4 °C | 5.1 °C | 52.07 mm |
| Annual | 6.6 °C | 17.7 °C | 1076.19 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 1 - Apr. 10 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 6b : -20.6°C to -17.8°C |
| Plant Hardiness Zone - 2012 | Zone 6a : -23.3°C to -20.6°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |