The One With The New Scarf

I've started (and re-started, and re-started) my new yarn. I think I've decided on this 4x1 ribbing. It's going okay as long as I pay attention. We had a bit of a rocky start, but we're doing okay, considering I'd only done about two inches of ribbing before this point. I wonder how long this scarf will take me? I wonder when we're going to have cool weather again so I can wear my new creations without sweating to death?