I understand that the predictions are not always correct. But for the most part they can tell what coastal regions will be feeling not accurately. But well enough to tell if ur going to see an early winter or not. They base all the measurements on the ocean currents. There is sensors and people testing temperature in the worlds oceans constantly.
Now for instance if a strong jet stream were to arise bringing water from the south that could only change water temps by .1 and that can have a major change on the weather. anyways long story short these are obviously predictions by what is being seen at this time.
Here's a link for all the canadians out there. It gives predictions on temperature and precipitation.
I'm Rick James Bitch.....
Show me your titties!