The official National Weather Service forecast for Watertown — 44.8994°N, 97.1151°W, population 20,643, 3.4 miles from I-29.
| Codington County | J | F | M | A | M | J | J | A | S | O | N | D | Year |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high °F | 21 | 25 | 38 | 53 | 66 | 77 | 82 | 79 | 72 | 57 | 41 | 26 | 53 |
| Avg low °F | 3 | 6 | 19 | 31 | 44 | 55 | 60 | 57 | 49 | 35 | 22 | 9 | 32 |
| Precip in | 0.6 | 0.6 | 1.1 | 2.3 | 3.3 | 3.5 | 3.4 | 3.2 | 2.5 | 2.4 | 0.9 | 0.8 | 24.6 |
1996–2025 normals for Codington County — the climate division Watertown sits in. All-time county record high 101.6°F (1988-08-01); record low -38.7°F (1994-02-09). Source: NOAA / National Weather Service.