Ask any expert and they'll tell you: the best time to see the aurora borealis is when the sky is clear. Sadly, the weather is the one thing you can't control – or predict.
Having said that, there are a number of factors that determine the likelihood and intensity of a display should the sky be clear. Factors that you can take into account when you are planning when to undertake your northern lights adventure.
We get the lowdown from some of the world's leading aurora experts on the best time to see the northern lights. Weather permitting, of course..
1. During Winter
It sounds obvious. The northern lights are best viewed when the sky is dark. And the sky is darker for longer during the Arctic winter. But that doesn’t stop people turning up during the summer asking where they can see the northern lights. James Minton, VP of Communications of Visit Anchorage, has lost count of the number of people turning up mid-summer looking for a display, despite the 23 hours of daylight.
2. During the Equinoxes
An equinox occurs twice a year, when the plane of the Earth's equator passes the centre of the sun. At this time the tilt of the Earth's axis is inclined neither away from nor towards the sun.
"No one is exactly sure why," says Steve Marple, a researcher in space physics at the Lancaster University. "But activity around the time of the equinoxes is much more intense."
The equinoxes fall around 20 March and 22 September. Check timeanddate.com for the exact time and date.
3. During a New Moon
The waxing and waning of the moon makes no difference to the northern lights. They can be seen at all stages of the moon’s cycle. But a full moon will lighten the sky, and may reduce the visual intensity of a display. Use a phases-of-the-moon calendar to plan your journey, or check the time the moon rises and sets if the moon will be full during your visit. Or simply embrace what the lunar calendar presents you. The full moon behind a display can be quite a spectacular sight.
You can find the moonrise and moon-set times for anywhere in the world at sunrisesunsetmap.com.
4. At the peak of the solar cycle
The northern lights become more active and intense around the peak of a sunspot cycle, and in the three to four years immediately following the peak. We are currently over four years into Cycle 24. For an explanation of what that means pop over to NASA’s webpage on Solar Cycle prediction.
5. At a certain time of the day
The northern lights are most commonly seen between 17:00 and 02:00. They don’t usually exhibit for long – they may only show for a few minutes, then glide away before returning. A good display may last for no longer than a quarter or half an hour, though, if you’re really lucky, it could extend to a couple of hours or longer.
Jim Thomas runs a website that will tell you what the aurora will be doing over the next few hours. And Aurora Watch, run by Lancaster University, has a real-time display about activity above the UK.
