We are also on this trip, having been on the Cloud in 2018 for the Reykjavik to Kangerlussuaq trip (which was fantastic!). There are no formal nights. I think my husband may have packed a suit jacket for dinner, but not a suit and I do not believe he ever wore a tie (but may have brought one just in case). AND he did not wear the jacket very often, generally a nice shirt and slacks as he would to work. As it is an expedition cruise, we found it more casual than we expected, but still "nice". We saw men in suits at dinner, but not many. Women wore nice dresses or slacks/tops (as one would to a nice restaurant); lunch is more casual. We DID have one night that was a bit dressy, but I had a pretty cardigan jacket that looked "dressy" but not formal with dark slacks. We quite enjoy Silversea and sincerely hope this cruise "goes". There IS a "fancy" restaurant that has a fee, but we never ate there. We did enjoy the Grille for dinner; this is at the outside bar area and you cook your own entree on an extremely hot lava slab. Something different and no fee; one does have to bundle but the area is under cover so that helps. Anyway, let us keep hoping that we get to go!!!