For some reason I have two weather widgets for Chicago set up on my Dashboard. Often when I look at them they’re not the same. My first though was that maybe one was for the airport while the other was downtown or something. But when I looked at the setup, they both just say “Chicago, IL.”
Perhaps the two widgets have different refresh cycles, and in the interval between the refresh on widget 1 and widget 2 the temperature changed by 3 degrees.