Mysterious substance falls from the sky

This afternoon as I left work there was this strange stuff coming down out of the sky. I wasn't sure at first what it was, but then someone said the stuff was called "rain." That kind of sounded familiar to me, and I have vague memories of this "rain" from months and months ago, but it's been so long that I'd forgotten what it was. We didn't get very much, and it's supposed to rain again on Thursday, but we need it. There has been an 18,000 acre wildfire east of here that's been burning since August 2, so any rain would be helpful.