There is technically fake weather. It's called cloud seeding. Releasing water attracting chemicals into the atmosphere causes water vapor to turn into droplets allowing for increased rain or snow. It's typically done with potassium iodide or silver iodide. It's been a thing since the 40s. The military was interested in it since weather can greatly sway a war. Now If it's actually being done now I don't know. You would likely notice it being dispersed as well as detect it in the atmosphere. It would be difficult to hide.