Climate
The weather is fairly temperate year round around Jökulsárlón but one should bring a waterproof winter coat and wear waterproof shoes. During the winter it may be cold, windy, and rainy so winter weather clothing is advisable.
Understand
Jökulsárlón literally means glacier lagoon Jökull - glacier, lón - lagoon. At the time when first settlers arrived in Iceland, the edge of Breiðamerkurjökull, an outlet glacier of the great glacier Vatnajökull, is thought to have been 20km further north than it is now. The climate began to cool in about the year 1200, the cold spell reaching a peak in the period 1600-1900, which is sometimes known as the "Little Ice Age". As a result the glacier advanced until about 1890, reaching a point only about 1km from the coast at Jökulsá river. The eastern part of the glacier eroded the sediments of Breiðamerkursandur to a depth of up to 300m below sea level, the sediment being carried forward by the river Jökulsá. Without the river the glacier could not have eroded such a deep basin, because it is the river that carries the sediment to the sea.
The warm period from 1920 to 1965 caused great changes in Breiðamerkurjökull glacier. It retreated very quickly, leaving a lagoon up to 190m deep where the glacier snout had been, and several kilometers of glacial moraines were exposed on both sides of the lagoon. The lagoon grew from 8km² in 1975 to 15km² in 1998. Large blocks of ice break off the edge of the glacier, which is about 30m high, keeping the lagoon stocked with icebergs.
The lagoon, when frozen, was used in a recent James Bond film in 2002 for a BMW chase scene {Die Another Day}.
Landscape
The white cap of Breiðamerkurjökull glacier dominates the lagoon and its icebergs. Jökulsárlón is separated from the sea by only a short distance, and the combined action of the glacier, the river that empties from the lake, and the ocean may eventually transform it into an inlet of the sea. There are plans to prevent this from happening, since the only road in the area passes over the narrow isthmus.