Daylight Savings Time always heralds a week or two of wailing and gnashing of teeth, mostly about being tired at odd hours and the consequences that come with it. One consequence of the change I discovered this year, which I hadn't noticed before, is the abrupt change in temperature. Specifically, I'm effectively commuting an hour later at night than previously, which means it's one hour's worth of nighttime colder.
We had a sudden change for the cold and rainy right at the start of November, but the time change accentuates it. In October, riding home in the dark was chilly but pleasant; now it's very cold, uncomfortably so. It has, very suddenly, become winter.
Having a clear line between "not cold enough for more layers" and "definitely cold enough" is helpful in its way, but it's still jarring.