In Global or Alliance chat, type "A storm is brewing" and post it. Once done, exit the chat screen and it will be raining in your city. To stop the rain, type and post the phrase "No more rain". *Please note: This code is seasonal only. I.E. It will only work during Spring, Summer and Fall seasons (real-time).
Your gold production will increase faster if you follow the quests in the game and always make sure to claim the title that is awarded to your character. Gold production increases the higher the title.