At the moment the exchange rate is a killer. As temping as it might be to buy warmer clothes once you arrive in Edinburgh, I would take what you can from the States. I know San Diego is not the best place to buy winter clothing, but almost everything will be much cheaper to buy before you leave. We just finished our 10th trip to England and Scotland and for the first time ever bought nothing to bring back except for one nice wool sweater my wife found for a reasonable price. At $1.89 to the pound, there was nothing (as far as clothing) that could not be bought for less in the U.S.