Being that I live in Wisconsin, I'm going to talk a little about being prepared for driving.  Now, my family tends to think I go a bit over board, but I'd rather be safe than sorry. Right now the wind chills are in the -30 -   -40 range, so I'm particularly careful to make sure I have extra items with us when we go anywhere. For instance: even if we don't wear them to leave, they come with us in case the car breaks down, won't start when we go to leave from like the store or something, boots, scarf,mittens,snowsuit,blanket,hats and when I can find them, those little packs of hand/foot warmers. My son and I went to Walmart a little while ago and just from walking to the car and putting the bags into car, our hands were frozen, just within a couple minutes. It took the drive of half way home for our hands to quit hurting. Sure made my son rethink why I bring all that with us.
Now, the reverse is true, preparing for summer. I always have sunscreen,bug spray,tennis shoes(if we're wearing sandals or flip flops)cold drinks,snacks. When the kids were younger, extra diapers,wipes,formula,extra clothes, etc.Also, bags, in case of throwups. Stroller, even if not planning on being gone long, didn't want to be stuck some where having to carry a little one.  Mrs. Prepper