What will the weather be like, Mr Marmot?

The Groundhog's day is celebrated in the USA to predict the weather of the following weeks. It is an American tradition celebrated on the 2nd February but it known what the weather will be like around the world. I think it can't be true because an animal can´t know how will be the weather. Apart from that, I think that traditions are interesting and good for the people because the can  have fun, as in celebrations and festivities.
In Salobreña, there is another similar tradition that says : " el día de la estrella, 40 días como ella". That means that it is taken one day in April, and depending on the weather of this day, there are going to be 40 days like it. Old people think that it is true, however I think that it is only an old tradition.