St. Lawrence Seaway Management Corporation

Seaway Opening and Closing Information

Closing of 2020 Seaway Navigation Season

• Radio Messages
• Seaway Notice No. 22
• Seaway Notice No. 21
• Notices to Shipping – Montreal/Lake Ontario
• Notices to Shipping – Welland Canal
• FAQ – Navigating the Great Lakes St. Lawrence Seaway Under COVID-19 Updated : April 9, 2020

Weather Information:

• Accumulated Freezing Degree Days (Dorval)
• Accumulated Freezing Degree Days (St. Catharines)
• Water Temperatures
• Weather Forecasts
  • The Weather Network: 14 Day Trend – Dorval
  • The Weather Network: 14 Day Trend – St. Catharines
  • Environment Canada: 30 day Temperature Forecast
  • NOAA: Monthly Temperature Forecast
• Freeze-up Forecast
• Water Levels and Environmental Data (MLO/Welland)
• Marine Forecasts and Warnings for Canada

Ice Information:

• Canadian Ice Service – Latest Ice Conditions
• Canadian Coast Guard – Ice Charts
• Canadian Coast Guard – Ice navigation in Canadian Waters