Kitchen Sink

We are only going away for a weekend and the amount of kit we have is ridiculous, these words are heard everytime we go away so something has to change as we normally travel by car but the big trip is by air. I havent travelled by air for a lot of years so packing light has never been a feature in my tarvel arrangements. Just checking a few items of essential clothing on the scales and the totals start to mount up. Seems like 23kg is about the standard for hold luggage and 6kg for carry on, doesnt seem to add up to a lot of kit. Camera, lens and tripod add up to 6kg so I will have to be carefull about over doing my carry-on bag. When The Boss went to Japan she managed to keep to her weight limits ok, but it was warm and wet when she went and she went for two weeks. We will be in Oslo for 2 nights on the way out and 1 night on the way back and 4 nights in Svalbard. We are going to Oslo a day early to have time to see the city in daylight. We dont know what the temperatures will be like in Oslo in March but we dont expect it to be warm! So do we take extra clothing or just use some of the stuff we are already taking, that is our dilema.We dont want to have too little clothing but we also dont want to have too much. The layers we are taking for Svalbard will be too hot for travelling round Oslo in as they are meant for standing still staring into space, so do we have to take another coat to cover our time in Oslo? We have lists of clothing and I can imagine they will be changed numerous times before we finally settle on what will be in the travel bags come March 16th.