Learning to predict the weather is actually a faux science. There is a lot that goes into it, but it’s really all guess work. Even the meteorologists on television have a hard time accurately predicting the weather. Really, the best you can hope for is learning how to guesstimate what kind of clothing you’ll need. However, you can go get a degree in meteorology. It’ll help you better understand how to predict the weather, but again, this is all really just guess work.
If you insist on learning how to predict the weather, learn the patterns of the area you’ll be in. Some areas get more rain around a certain time of month than others do. Otherwise, leave it to the professionals.