Hello,
I've been browsing the Living Atlas and haven't been able to find a layer for Candian weather data that I can add to my web map. I am looking for a similar version of the US one shown here: https://pdri.maps.arcgis.com/home/item.html?id=da53700b1f324cc685c4d3bcc00c12fc
There is a lot of information shared as WMS service here: http://geo.weather.gc.ca/geomet/?lang=E&service=WMS&request=GetCapabilities
You can add the service to your map in ArcGIS Online (or consult it using Desktop).