Winter....bites me in the butt every time

Why must Xan get so upset every year when it's time to switch to a winter coat??? This morning went really smooth. He DID wet the bed last night, but now he will change his own clothes. Normally he comes into our bedroom with different pajamas on and I know what has happened. This morning, Chris found him in bed with Tyce, which I have to admit I thought was really cute :) Wet pajamas laying on the floor which is kinda gross, but whatever. I fixed the boys donuts, turkey bacon, bananas and drinks and they both ate good. I had prewarned Xan that he had to wear his winter coat today which he did NOT like at all. So, when I go to help him with it this morning, he starts crying and is SO upset. He starts saying that "everyone doesn't wear a winter coat" and jumbling some other things. He keeps trying to get away from me too. In the car this continues and he says he doesn't want to wear his "stupid coat." This is sad, but I was thinking "wow...great adjective." We pull up to school and he is still clearly upset. He will say he is sorry and then continue to pull on his coat. I know he can't help part of this, but I still feel my patience tested big time during these moments. He hates going to school when he thinks I'm mad and I hate leaving him there upset. I did email one of his teachers, so hopefully they will know why he may be testing their patience today. People used to talk about how rigid kids with autism were in their routines. Xan used to not be like this really, so I didn't understand it. Now, our lives are filled with routines. Sometimes he can deviate, other times he gets upset. He has had lots of speech and academic gains over this past year, but still lots of issues. I know he will be apologetic when he gets home, poor guy. I hope one day he will grow to understand what is a big deal and what is not. Until then....