DIY web site Instructables details how to predict the weather by glancing at the sky and—more specifically—the clouds.
Being able to predict the weather by observing cloud formations is a skill that is somewhat lost on us modern humans. Most of us can easily look at a cloud and see the unicorn or ice cream cones, but very few of us can look at clouds and see the approaching cold front.
The post focuses on first highlighting and identifying different cloud formations and what they mean to the weather, then describes how to put that information to use. You may not be able to out-forecast your local weatherperson off the bat, but a better knowledge of the clouds and climate can't hurt. While you're at it, check out a few other methods (like smell) of predicting the weather without checking the forecast.