Precipitation and radar accuracy

I've been using this app a lot with the premium version and generally speaking I really do like it. Lately, I've been seeing a lot of discrepancies between this apps data and what is actually happening so I'm wondering why the accuracy has been getting worse. Comparing this to Google's built in weather predictions today for example Ventusky is showing ~0.2mm of rain, while Google is showing 5mm or so. The other day at had environment Canada warnings and a really bad wind/rain storm, and again Ventusky showed almost no rain and that the storm would completely miss us. I'm in Kitchener Ontario and I'm seriously getting concerned about whether or not this is even useful anymore as the more I look the more it seems off. What sources does this app use?

Andrew Ward
The data sources used by Ventusky are described here: https://my.ventusky.com/guide/help/data-sources-2/

You can always choose from several different models and data sources. Ventusky itself does not produce weather forecasts, and the overall quality of the available data sources certainly has not declined.

Next month, we will add another new model for your region. It has been under development by NOAA for the past two years and is expected to become operational within the next few weeks; it is currently still in testing. It will provide forecasts up to 48 hours ahead and has shown better results than the models currently available. At the same time, you will have another independent source to compare with the others.