It is always a good idea to check the weather before you pack for a trip. Today, that is easy with the internet and cell phone apps if you have a smart phone. There is nothing worse then packing for a week at the beach just to arrive to clouds and rain and find you have not packed a sweater or sweatshirt. Several years ago I took a trip to Key West in January. The temperature dipped into the high 40's and I had to find something to keep me warm. You can imagine how surprised I was that not even the local Kmart had sweatshirts. They told me it never got that cold in the tropics and they sold only t shirts for the tourists. I always carry a plastic rain protector that I buy at the Dollar Tree. They come in packs of two so I usually put one in the glove compartment of my car too. They come in handy and are so cheap that it doesn't matter if you lose one or if it gets ripped.
