Hi, and thank you for your interest!
World-Weather is being translated using Weblate, a web tool designed to ease translating for both developers and translators.
Translation project for World-Weather into Chinese (Simplified) currently contains 232 strings for translation and is 42.1% complete.
If you would like to contribute to translation of World-Weather, you need to register on this server.
Once you have activated your account just proceed to the translation section.