The official National Weather Service forecast for Port Arthur — 29.8852°N, 93.9423°W, population 116,819, 16.7 miles from I-10. Forecasts here are written by NWS LCH, this county’s forecast office.
| Jefferson County | J | F | M | A | M | J | J | A | S | O | N | D | Year |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high °F | 63 | 66 | 72 | 78 | 85 | 90 | 92 | 92 | 89 | 81 | 72 | 65 | 79 |
| Avg low °F | 43 | 48 | 54 | 60 | 67 | 73 | 75 | 75 | 70 | 61 | 52 | 46 | 60 |
| Precip in | 4.7 | 3.1 | 3.4 | 3.7 | 4.9 | 6.1 | 5.9 | 6.4 | 6.4 | 4.8 | 4.5 | 4.5 | 58.4 |
1996–2025 normals for Jefferson County — the climate division Port Arthur sits in. All-time county record high 106.8°F (2023-08-28); record low 10.7°F (1989-12-23). Source: NOAA / National Weather Service.