Your head can feel very cold if you lose your hair due to chemo (as I did). I made an "Easy-fit Ribbed Hat" (with a pompom on top) using 'chunky' wool (approximately one and a half 100 gram balls) and it only took me two nights to knit. The pattern I used was one that I found on the internet from www.redheart.com. I hope this helps. One more little tip - if your head feels really cold (bearing in mind that Autumn is approaching) try wearing two hats, a thin one tucked inside a thicker one.