Start of rant****
Since when did September 1st become the first day of autumn? Maybe it was about the same time we dumbed down and started talking about "going to uni". In my day(!), every school child knew that autumn started on September 21st and people could actually be bothered to say all five syllables of "university".
This morning, I heard a chirpy weather forecaster say that we use September 1st as the first day of autumn because it is easier to remember. Never mind that we might have several weeks of good weather left. Using that logic, Christmas Day will be on December 1st this year. End of rant****
But just to show that I can move with the times, here is what I am working on at the moment. When I bought this King Cole Country Tweed at an outdoor market, the sun was blazing and it looked like pink and grey. At home, I realised it was more like autumnal rust and brown. My original plan for a baby item had to change to a scarf. It is beautifully soft. But there is no way on earth that this is a double knit yarn. It feels like 4 ply and takes forever to crochet with.
I have made this scarf many times and know that I would be finished by now if this was a real double knit yarn. The stallholder told me the yarn had been discontinued. I can see why. It is perfect for a soft scarf. I have checked on Ravelry and many projects made with this yarn tend to be scarves and shawls. But there are also some cardigans and jumpers. I can only assume that the knitters/crocheters avoided sizing disasters by making a tension square first.
So, if a double knit yarn feels more like 4 ply, then it probably is. Likewise, if it feels like summer and looks like summer, it is still summer!