Some Chinese investor needing a safe heaven for their assets (and/or, in case some purge happens like with Jack Ma, for their family) that can't be seized at random by the CCP does not care at all about the weather, only about the country showing a spine to China. That is why the real estate market of Canada is so thoroughly messed up - a third of Vancouver's market, for example, was Chinese (https://www.fortunebuilders.com/one-third-of-vancouvers-real...).
Canada can get quite cold, but Vancouver is actually relatively moderate and is borderline Mediterranean due to its west coast location. Beijing gets both much colder and much hotter on a regular basis.
Also, air quality in Vancouver is significantly better than in Beijing, which would have more impact on living conditions than just climate by itself.
Weather and the high cost of living in all the major Canadian cities (compared to the average tech income) were the two main reasons wife and I decided to move down South. Don't regret it for a moment.