Summer

Jökulsárgljúfur is in the northeast of Iceland. It may sound strange, but summer temperatures are usually higher in North Iceland compared to South Iceland. The reason is when southerly winds cross the land, they accumulate heat and bring warm air to the north (often in the range of 20-25°C). The cliff walls of Ásbyrgi and Jökulsárgljúfur canyon also provide shelter for trees and bushes, and all together this creates a pleasant environment for visitors at Jökulsárgljúfur. However, northerly winds can also bring cold air and rain so it’s always better to be well prepared and ready for any kind of weather.

The north is also the land of the midnight sun: From 12 June to the end of June the sun does not set in Ásbyrgi, resulting in bright and quiet nights and unique atmosphere.

Autumn/Fall

Jökulsárgljúfur’s appearance starts to change early September when the birch leaves start turning yellow, soon followed by the tea-leaved willow. At the end of September, when the rowan is adorned with red berries and orange leaves, the overall view of Ásbyrgi is a symphony of colours that lasts well into October, making it a beautiful place to visit.

Winter

It is very important to understand that Ásbyrgi is in a lowland area, while Dettifoss is in an upland area. Therefore, winter conditions can vastly differ between those two locations, especially due to the amount of snow accumulating at Dettifoss.

In times of changing climate, it has become hard to predict when the first snow of the winter falls, and when there is enough snow cover to last the winter. But the upland roads between Ásbyrgi and Dettifoss (roads 862 and 864) usually close in October because of snow. Ásbyrgi, however, can always be reached by road 85 but reaching Dettifoss is subject to conditions on the south section of road 862 (which connects with Route 1).

Daylight hours are limited in November, December and January, but in February one can really tell that the day is getting longer and brighter. It also helps that usually there is enough snow cover by then, with the white snow lightening up the environment. Usually there is thick snow cover at Dettifoss by this time which lasts until May. As the roundtrip hike from the parking to the waterfall is about 2 km it is recommend having good shoes/boots and sometimes traction devices are necessary.

Spring

In April, the snow usually starts to melt and the ground starts to thaw. Trails and vegetation are usually frail during the period and sensitive to use. The roads between Ásbyrgi and Dettifoss are always impassable and closed during this time. Road 864 usually opens at the end of May, but 862 not until mid-June.

Road conditions

The Icelandic Road and Coastal Administration provides updated information about current road conditions.

Daylight hours

To get a rough idea about daylight hours at Dettifoss, please check the table below:

DETTIFOSS       Sunrise    Sunset
October 21:           8:22         17:20
November 21:       10:14        15:30
December 21:       11:37         14:32
January 21:            10:39        15:56
February 21:         8:49          17:51
March 21:              7:03          19:24
April 21:                 5:04         21:06
May 21:                  3:07         22:59
June 21:                 0:00        00:00 (sun does not set from June 16 to June 26)
July 21:                   3:11           23:14
August 21:            5:06          21:14
September 21:     6:54          19:14

[Based on October 21, 2017 – September 21, 2018, courtesy of www.suncalc.net]