Astoria, South Dakota has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 0.7 °C (low) to 11.7 °C (high). Annual precipitation averages 703.6 Millimeters. Astoria is located in USDA Plant Hardiness Zone 4b. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -15.8 °C | -5.9 °C | 17.02 mm |
| February | -13.5 °C | -3.4 °C | 16 mm |
| March | -6.9 °C | 3.3 °C | 35.05 mm |
| April | -0.1 °C | 11.8 °C | 66.04 mm |
| May | 7.2 °C | 19 °C | 94.23 mm |
| June | 13.1 °C | 24.4 °C | 120.65 mm |
| July | 15.6 °C | 27.2 °C | 89.15 mm |
| August | 14.4 °C | 26.1 °C | 82.3 mm |
| September | 9.5 °C | 21.9 °C | 80.26 mm |
| October | 1.9 °C | 13.9 °C | 55.63 mm |
| November | -5.4 °C | 4.7 °C | 26.92 mm |
| December | -12.2 °C | -3.1 °C | 20.32 mm |
| Annual | 0.7 °C | 11.7 °C | 703.57 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 4b : -31.7°C to -28.9°C |
| Plant Hardiness Zone - 2012 | Zone 4b : -31.7°C to -28.9°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |