Kp Index

It's impossible to predict the aurora accurately, but geomagnetic activity - measured by the 'Kp index' - indicates when the lights are most likely to appear. The higher the Kp index the better your chances. Ratings of 8 or above are very rare, and many of the photos included here were taken at low Kp numbers.

There are a number of apps and websites that report on the Kp index. A great source of up-to-date information is the website of the Icelandic Met Office.

Since the aurora is a million times dimmer than sunlight, it cannot be seen during the day. From 9pm until 2am tends to be prime viewing time. If you need your beauty sleep, you'll find that many hotels offer an aurora alarm service.

The weather conditions are vital. You'll need clear skies, and a small moon will make it easier to spot the aurora's glow. Heading away from light pollution will maximise your chances of a glimpse, although the very brightest auroras can be seen from cities and even through thin clouds.

You could even try to ensure your inbound and outbound flights are after dark, as some of the best views of the aurora are from high-altitude aircraft.

Trips and tours abound, but Iceland is one of the best places for independent travel to the lights, where you won't be bound by an itinerary. Many visitors hire a car for a night or two and drive out of Reykjavik into the wilderness. The hours of darkness increase the further north you travel, increasing your chances of catching a sighting. The Westfjords region in the northwest is a popular destination for this very reason. Thingvellir National Park is another good choice, as is the geothermal zone of Landmannalaugar.

Check all these boxes and then all you have to do is cross your fingers, wrap up warm, sit back, and wait for the show.