The official National Weather Service forecast for Saint Helens — 45.864°N, 122.8065°W, 4 miles from I-5. Forecasts here are written by NWS PQR, this county’s forecast office.
| Columbia County | J | F | M | A | M | J | J | A | S | O | N | D | Year |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high °F | 45 | 48 | 52 | 58 | 65 | 70 | 78 | 78 | 72 | 61 | 50 | 44 | 60 |
| Avg low °F | 34 | 34 | 36 | 38 | 44 | 48 | 53 | 53 | 49 | 43 | 37 | 34 | 42 |
| Precip in | 8.5 | 6.4 | 6.3 | 4.0 | 2.9 | 1.8 | 0.4 | 0.7 | 2.2 | 5.1 | 8.7 | 9.9 | 56.9 |
1996–2025 normals for Columbia County — the climate division Saint Helens sits in. All-time county record high 104.7°F (2021-06-28); record low 2.5°F (1989-02-04). Source: NOAA / National Weather Service.