The official National Weather Service forecast for Portage — 43.5391°N, 89.4626°W, population 10,555, 2 miles from I-39. Forecasts here are written by NWS MKX, this county’s forecast office.
| Columbia County | J | F | M | A | M | J | J | A | S | O | N | D | Year |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high °F | 27 | 31 | 44 | 57 | 69 | 79 | 83 | 80 | 74 | 60 | 46 | 32 | 57 |
| Avg low °F | 11 | 14 | 24 | 35 | 46 | 57 | 61 | 58 | 51 | 39 | 28 | 17 | 37 |
| Precip in | 1.3 | 1.3 | 2.3 | 3.4 | 4.2 | 5.3 | 3.8 | 4.2 | 3.2 | 2.7 | 1.9 | 1.7 | 35.3 |
1996–2025 normals for Columbia County — the climate division Portage sits in. All-time county record high 103.2°F (2012-07-06); record low -39.0°F (1951-01-30). Source: NOAA / National Weather Service.