I found only one post with someone else asking for environment canada weather data; but no replies.  

This morning, I'm sitting in my office, and see the sprinklers come on at their regularly scheduled time.  Unfortunately, my whole area is under a Flood Warning, and there is 200mm of rain forecast this week.  50mm has fallen in the last 2 days.

NOAA forecast is predicting 0mm of precipitation for the next week, according to the "Rain QPF" graph."   Looks like NOAA only covers the US.

What do Canadian RainMachine users use?

I used to use DarkSky when I had HomeAssistant controlling my watering but even it was unreliable / inaccurate.  So I did my own hackey environment canada push which was pretty spot-on.