If you join a cruise, the company will provide you with detailed informations about the voyage and the equipment you need. Please read these informations carefully – good preparations are the foundation for the success of your journey!
Being frequently asked about the subject, I want to offer my opinion regarding clothing and some basic guidelines:
Clothing is a very personal issue. Under the same conditions one person might feel well in light clothing and the next one freezes despite of a warm jacket his ass off (oops… sorry!). In the end, you have to decide yourselves what works for you and what doesn’t.
Usually you will not encounter temperatures way below zero. In Svalbard, for example, average summer temperatures range from +1 to +6°C. But depending on wind, possibly absent sunshine and your (in)activity you may experience the temperatures as colder (wind chill). On a calm and sunny day (not everyday conditions!) you may indeed feel quite hot. Greenland’s protected fjords can be quite warm, Antarctica tends to be a bit colder. South Georgia is often very windy (well, it can be windy anywhere, but there even more so).
The layer principle is always good. Weather conditions change quickly, and maybe at first you spend a while in a zodiac (inflatable rubber boat) under rough conditions without moving, then the bright sun comes out and you go and climb a little mountain. Thus you should always be able to adapt quickly. Using several layers enables you to add or remove another sweater which you can then store in a little daypack which you should always have with you.
The uppermost layer should always be wind- and waterproof (even in sunny weather – splashwater during zodiac transfer!). Modern outdoor clothing with breathing membranes is good, but for short landings cheaper rainwear will usually do the job.
Always have gloves, scarf and a wooly hat with you – at least in your daypack. An old Inuit saying goes like “If you have cold feet, cover your head”. It’s true! A spare set of gloves can be useful in wet conditions. A lighter pair of fingered gloves will still enable you to handle binoculars and camera.
Jeans or similar are useless.
Protect your camera gear against weather and splash water!
Don’t underestimate sun radiation in high latitudes – always use sun cream and good sunglasses!
Rainproof gear is good, sunshine is better.
Shoes are sometimes an issue. I use always wellingtons (wellingtons, rubber boots – is there any difference…?). But not the cheap ones may you use in your garden – get solid hiking rubber boots with good soles with deep profile. Please – if you spend several thousand € for a trip, don’t try to save a few bucks on crucial equipment! They are much better than most people think, I have used boots like that for my longest day trips (up to 40 kilometers) without getting blisters. Staff members on your cruise are usually not keen on breaking their backs to carry you in and out of the zodiacs, and it is not nice if a whole group has to take a detour because one person is unable to cross a little river or swampy area because he/she does not have rubber boots (remember: the arctic is polar bear country. In Svalbard and East Greenland you cannot walk on your own, but you have to stay with your group!). Take rubber boots a number larger than you would at home to allow for a thick extra pair of socks.
I personally use a flotation coat (usually not useful for you unless you are a Zodiac driver) or:
first a layer of thermal underwear.
Solid Gore-Tex-pants are always good.
A warm pullover and a Gore-Tex jacket.
I always carry a little daypack with scarf, woolly hat, gloves.