Quick answer
Certain winds bring certain weather, and certain talk brings certain faces. The verse pairs two reliable causes.
Read both lines
The first line is a weather observation and readers have argued about it for centuries, since a north wind does not obviously bring rain in Israel, and various solutions have been proposed. The saying's logic does not depend on resolving that. Whatever the meteorology, the structure is a known cause producing a known effect.
The second line supplies the human version and its Hebrew is literally a tongue of secrecy, talk done out of sight. What it produces is פָּנִים נִזְעָמִים, indignant faces, and the plural is worth noticing: not one wounded person but a room full of angry ones. That is what backbiting reliably makes. The verse does not threaten the backbiter with consequences. It simply reports the weather he generates.
Related: Proverbs 26:20 · Proverbs 16:28 · Proverbs 20:19 · Proverbs 11:13
New King James Version®, Copyright © 1982, Thomas Nelson. All rights reserved. Full copyright information. Scripture provided by API.Bible.
Go Deeper
If this verse has been used to put weight on you that it was never carrying, ask about it directly.