Elizabeth Zimmerman said the best time to knit mittens is the summer. They are small and light and don't fill a sweaty lap with great swaths of wool. That waiting until winter when mittens are actually needed is too late to give them the time and attention knitting mittens deserves.
I have 2 pairs of mittens in time out and a glove too. All have been there a year or more. By the end of May I hope to have them finished or decided they are done and throw them away. I just cast on a new pair of mittens too.
However, right now I'm knitting on a scarf and some socks. Mittens and self imposed knitting just isn't appealing today. It's hot. I'm exhausted and stretched a little too thin. My being wound just right maybe doesn't apply to May. But with some deadlines whooshing up by the end of this weekend it should be a little better.