Firsthand experience of this. Was at the Grand Canyon. Beautiful cloudless day. Weather reports were that it would continue through the weekend. No call for rain or anything else. This was in the Fall, so it was a bit crisp, but not cold. Around 1pm I see chemtrails forming, criss crossing over the Canyon on the South Rim. Weird, they were in a sort of X formation and made no sense. Am a pilot. I know how winds aloft works. I know how flightpaths work. For that many different flight paths to appear in the sky in a matter of half an hour, there'd have to be major wind shears and shifts. By the time they were done, the sky had a plaid design.  Lo and Behold, at 4pm it suddenly clouded up. Huge black thunderclouds (again, NONE of this was forecast!) started to build. By 6pm it was pouring rain. We had plans for an outdoor concert on the rocks that night. Concert planners were assured it was a cloudless and rainless night. But - um - "Climate Changers" -- had other ideas.  I used to think the chemtrail folks were a little on the cuckoo side. Not anymore.  ... Edit to add: When our lefty friends insist that Climate Change is manmade, let's start agreeing with them. Then point them to Chemtrails and that NASA couldmaking machine - https://www.invidio.us/watch?v=s5KgYFvsW0c Make them think!