Best Time to See the Northern Lights

Timing comes in layers: the year, the season, the night and the hour. Getting each layer right raises your odds, even though no date can guarantee a display.

Best season: dark nights

The aurora happens all year, but you can only see it when the sky is dark. In summer, northern places have short nights or none at all, so the light is washed out by twilight.

For the northern US, southern Canada and the UK, the practical season runs from late August to mid April. In Alaska and the far north, the window is a little shorter because summer twilight lasts longer.

In the Southern Hemisphere, the seasons flip. Tasmania, southern mainland Australia and New Zealand have their best viewing from about March to September.

Best hours of the night

Activity tends to peak around magnetic midnight, when your location faces directly away from the Sun in Earth's magnetic field. For most of North America this falls close to local midnight.

A good rule is to watch from 10 pm to 2 am local time. Displays can start earlier or run until dawn during strong storms, so it is worth checking back if conditions stay active. Remember that daylight saving time shifts the clock by an hour.

The equinox effect

Geomagnetic storms are more common around the March and September equinoxes. Scientists link this to the Russell-McPherron effect, first described in 1973.

Around the equinoxes, the tilt of Earth's magnetic field relative to the solar wind makes it easier for a south-pointing solar wind field (negative Bz) to connect with Earth's field. That lets more energy in. The effect raises the odds, but it does not make every equinox night active.

Moon and weather

A bright Moon washes out faint aurora, much like city lights do. Strong displays are visible even under a full Moon, but weak ones may disappear.

• The week around new Moon gives the darkest skies.
• If the Moon is up, face away from it and use a building or trees to block its glare.
• Clear skies matter more than anything else. Check a cloud forecast as well as the aurora forecast.

The solar cycle

The Sun goes through an activity cycle of about 11 years. NOAA and NASA announced that solar cycle 25 reached its maximum period, with the smoothed sunspot number peaking at about 160.9 in October 2024.

The years after a maximum are still a good time to watch. Large storms often continue during the declining phase, and fast solar wind streams from coronal holes become more common. The record G5 storm of May 10-11, 2024 and the G4 storm of October 10-11, 2024 both came near the peak, but strong events can still occur through the rest of the decade.

Using the forecasts to time your night

Use the forecasts in layers:

1. The 27-day forecast shows likely active days, based on the Sun's rotation.
2. The 3-day forecast shows expected Kp for each 3-hour block.
3. On the night, the live Kp index and the aurora map show what is happening now.

Forecasts beyond a day or two are rough. A CME can arrive earlier or later than expected, and its strength is hard to predict until it reaches Earth.

Questions people ask