Have done the New Year in Iceland trip twice with JY. Enjoyed the first so much, went back again! As previously said lots of warm layers, waterproof/wind proof outer layer, good walking boots and grippers. Expensive country! Extra trips well worth doing, if you do the northern lights trip, be prepared to be out late, must take plenty of clothing, you may be in middle of field in darkness just waiting, but they keep bus there for sheltering, and Just You use same local guide who is excellent and is fabulous trying to get you to spots where the light prediction is good. I enjoyed both New Years Eve dinners, but know they have changed the venue for this years trip, due to the restaurant no longer offering this, so cannot comment. Don't forget swimsuit for the Blue Lagoon. Enjoy it!