We have a group at work heading to the North Slope next week for the first time.  They are scampering for Artic apparell.  I have heard that you can't even fly from Anchorage to Dead Horse unless you are wearing Artic gear.  The pilots won't let you on the plane!  
Of course, it is -28F on the slope and only about an hour of sun light at this time of year, so it doesn't warm up much.  Keep your hands, feet and ears warm and you should be okay!