Matt Yglesias has concerns (warning – his post contains spoilers):

“The whole movie also drove me to constantly want to quibble about characters not wearing hats at various points. If you walk outside in Cambridge, Massachusetts during the winter without a hat on, your ears get pretty f***** cold, even if you’re just walking a few blocks. The idea that you could be outside riding on a boat cruising through the Antarctic Ocean without a hat on is absurd. Similarly, running around a structure buried deep beneath Antarctica (it’s colder underground) without a hat for an extended period of time is ridiculous. And fighting an alien on the surface of Antarctica without a hat or a coat is beyond insane.”

He’s right, but I think this is something of a sci-fi tradition. I mean, it wasn’t that often that we saw Captain Kirk in a hat.