forecast
detailed forecast
| Extented weather forecast for Cornwall Ontario and the Seaway Issued by Environment Canada at 1530 ET Sun Sep 13 2026 |
| Tonight: Mainly cloudy with 40 percent chance of showers. Risk of a thunderstorm early this evening. Wind west 20 km/h becoming light this evening. Low 11. Monday: A mix of sun and cloud. Becoming cloudy late in the morning. Wind northwest 20 km/h becoming light in the afternoon. High 19. Uv index 4 or moderate. Monday Night: Clearing in the evening. Fog patches developing overnight. Low plus 5. Tuesday: A mix of sun and cloud. High 21. Tuesday Night: Cloudy periods with 60 percent chance of showers. Low 15. Wednesday: Cloudy. High 23. Wednesday Night: Cloudy. Low 14. Thursday: Cloudy with 40 percent chance of showers. High 22. Thursday Night: Cloudy periods. Low 11. Friday: A mix of sun and cloud. High 19. Friday Night: Clear. Low 6. Saturday: Cloudy. High 18. |
regional radar

■ Cornwall
Rain Snow Ice Mix














