if weather spells do work [it's debated] i would not recommend a beginner to cast them. it's a form of high magic, and high magic is far more dangerous than low magic, if you don't know what you're doing and it backfires badly. it's very dangerous for a beginner to be casting powerful magic.
also, you'd need to know how the particular magic works, weather spells in this case. you're not conjuring storms, you're moving weather patterns and this can cause terrible consequences. since you're from the dessert, it's suppose to be dry, too much rain can cause flooding, and the habitat could start to die. also, you've move the weather pattern away from one area, so let's say there's now a drought as a result. this isn't always a bad thing to cast certain spells [think of witch doctors doing rain dances in the dry seasons] you just need to be aware of what's happening.
as well, you need to know the climate, casting a spell for snow in the tropics will fail, or show up as rain. you can't make the weather change to be something it normally isn't for the region. on top of that, you need to know when you should cast. i love rain too, heck, i love snow, but casting a snow/rain spell whenever i feel like a snowy/rainy day will have really bad results. [though if it doesn't start snowing soon i'll have to take matters into my own hands lol just kidding]
your friend did give some great advice, one big reason why a spell will fail is if you're not concentrating, meditation can help you focus on the task at hand and not 5 or 6 other things as well. keep up with the meditation, but i'd not toy with nature. [my opinion anyway]