Perhaps you've heard of people being able to predict when a storm is coming with their "trick knee" or because some other joint starts to hurt. It took me awhile to realize that their is a connection between my headaches and the weather. From my own experience, if it is going to rain, the likelihood that I'm going to get a headache goes way up. Add in some of my other headache triggers, like hormonal changes, alcohol, and stress, and I'm in for a perfect-headache-storm.
I know I am not alone in my weather-induced migraines, for I just discovered that accuweather.com has a migraine module on their local forecast. The website shows that I am currently experiencing headache weather (it's raining). However, according to the their iPhone app, my migraine risk is low.
At any rate, thankfully I don't have a headache today and my forecast for the weekend looks pain free.