This month may be the best time to discover northern lights for nearly a decade, as the combination of the “equinox effect” and supercharged solar activity will make auroras more likely. But exactly where and when they will appear is still up in the air.
At 10:46 a.m. EDT (2:46 p.m. UTC) on Friday, 20 March, the sun will cross the celestial equator, marking the spring equinox in the northern hemisphere and the autumn equinox in the southern hemisphere.
The Equinox Effect
This “equinox effect,” which doubles the chance of aurora activity around the spring and fall equinoxes, was first explained by scientists Christopher Russell and Robert McPherron in a 1973 paper in the Journal of Geophysical Research.
They argued that auroras were more likely in March and September because the south-pointing magnetic fields of the solar wind cancel out the Earth’s north-pointing magnetic field, making it easier for the solar wind to flow along magnetic field lines. Effectively, the door swings open, allowing more of the charged particles colliding with oxygen and nitrogen atoms in the upper atmosphere to cause the aurora.
The March equinox comes as solar maximum — the peak of the Sun’s 11-year cycle of solar activity — is nearing its end. During solar maximum, the Sun’s magnetism is at full strength. NASA, the National Oceanic and Atmospheric Administration (NOAA) and the International Solar Cycle Prediction Panel reported that the Sun had probably reached solar maximum in October 2024but they added that it would not be possible to confirm that for months or years.
The Sun’s magnetic intensity is calculated by counting sunspots – cooler areas on the Sun caused by a concentration of magnetic field lines – on the surface. The number of sunspots is now decreasing, and the British Met Office announced this in January activity appears to be decreasing. That means fewer solar flares and, crucially, fewer coronal mass ejections — clouds of charged particles that can travel toward Earth to produce auroras.
according to NOAA‘s Space Weather Prediction Center, Solar Cycle 26 is expected to begin sometime between January 2029 and December 2032, with solar activity likely to remain low during that time.
Will there be a noticeable equinox effect in March? Conditions may produce the best Northern Lights until the mid-2030s, but that doesn’t mean we should expect to see them at more southern latitudes in the Northern Hemisphere.
In the end, everything depends on solar activity, and it is difficult to predict in advance. While early February produced the most active sunspot of the current solar cycle – resulting in auroras at much lower latitudes than usual – this monster spot has since disappeared. Unfortunately, there is no way of knowing if a new one will emerge to take its place in time for the equinox.
