What is the connection of Ru'ach Tzafon to rain?
Rashi: The north wind begets and creates the rain.
Malbim: Wind hidden in vapors begets rain. Vapors rise from the ground full of light (not heavy), airy Ru'ach. Via this, they are elevated above. When the wind goes out, drops of water fall, for they become heavy when the wind departs, and there is rain. Even though the wind is not seen, when there is rain, we know that the wind begat it.
What is the connection of wind causing rain to an angry face and hidden Lashon?
Ta'anis 7b: Rain is withheld only due to people who speak Leshon ha'Ra.
Rashi: Techolel is an expression of hidden. Hidden talk, i.e. Leshon ha'Ra, makes Hashem's face angry, just like the north wind causes rain.
Malbim: Hidden talk begets an angry face. Even though the stormy Ru'ach that the Leshon ha'Ra begets is hidden deep in the heart, it is recognized via seeing an angry face.
