even though it say to use circular needles?
It depends. Circulars can be used for knitting in the round or knitting flat, back and forth, but generally when a hat pattern asks for a circular needle it means that it is going to be knit in the round. In that case, you cannot use straight needles in its place. There are hat patterns that are knit flat and then seamed up one side, which can be knitted with straight needles.
There are some hat patterns which easily convert to using straight needles, and some that don’t.
For instance, I saw a pattern for a 3x2 rib that I wanted to use but I only had straight needles handy, so I converted it to a flat pattern easily enough.
If you want to post the pattern, maybe we can help you figure out how to convert it?
If it’s a pretty simple hat pattern you could probably knit it flat and then seam it up the sides, it might take a little figuring since they assume that you’re ALWAYS on a right side row and such, but it can probably be done. The best way to know is to try!!
If you don’t already have a specific pattern chosen there ARE hats out there for straights, for example Tychus hat at knitty.com
Wow that Tychus hat is something! She says it’s super easy but…
I’m not so sure about that. I’m know I could do it when I’m ready to concentrate. I just saw a very simple hat knit on straights that’s seamed… I can’t remember where but will watch for it.
This is not the right answer but here is a very cool hat (and check the guy!)
that I’m going to make because I like the simplicity of it yet it looks really comfy.
double pointed needles instead of circular (which I happen to love)http://www.y2knit.net/QuickHatOct04.pdf
http://www.wrights.com/class/needlework/knithat/knithat.htm
http://www.headhuggers.org/patterns/kpatt08.htm
Here are some hats knit on straights, they all look fairly easy.