For when it is not completely freezing outside or when your kind of cold inside.
Nina always has cold hands inside, especially when she is sitting at the computer too long. I made her these hand warmers out of Knitpicks Shine Worsted. They are soft pima cotton, she always feels itchy with wool, even merino. She also did not want any thumb so it would be more comfortable to hold a pen or pencil when drawing.
I made my hand warmers from Knitpicks Swish DK.
I don't use a pattern for the hand warmers any more I just figure out my gauge for the yarn and start knitting. This of course leads to lots of trial and error single hand warmers until I get it right, but they knit up fairly quickly so it's not such a big deal.