The official National Weather Service forecast for Yankton — 42.8711°N, 97.3973°W, population 16,022, 31 miles from I-29.
| Yankton County | J | F | M | A | M | J | J | A | S | O | N | D | Year |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high °F | 29 | 34 | 47 | 60 | 71 | 82 | 86 | 83 | 77 | 63 | 47 | 33 | 59 |
| Avg low °F | 11 | 13 | 25 | 36 | 48 | 59 | 63 | 61 | 52 | 39 | 26 | 15 | 37 |
| Precip in | 0.6 | 0.8 | 1.5 | 2.9 | 3.6 | 4.1 | 2.9 | 3.3 | 2.7 | 2.3 | 1.1 | 0.9 | 26.7 |
1996–2025 normals for Yankton County — the climate division Yankton sits in. All-time county record high 107.6°F (1988-06-22); record low -32.2°F (1970-01-19). Source: NOAA / National Weather Service.