It's This Cold...Again

I knew it was going to be below zero this morning.  But I woke up to -18 degrees Fahrenheit this morning.  I'm supposed to lead a Moonlight Snow Shoe tonight at 7pm.  If it's this cold then, I wonder if I should take a squirt bottle with me?  This is what I did 2 winters ago when it was -21: [youtube]http://www.youtube.com/watch?v=a8Hy1Pxyk-Y[/youtube]