Why March is the best month to see the northern lights (Image Credit: Space.com)
One of the most common questions aurora chasers get asked is “When is the best time to see the northern lights”. While auroras are fickle creatures and difficult to predict with pinpoint accuracy, there is evidence to suggest that March is the best month of the year to see them.
The northern lights, or aurora borealis, are caused by energetic particles emitted from the sun through a variety of processes including outpouring solar wind and eruptive coronal mass ejections (CMEs). When these energetic particles hit Earth, our magnetic field funnels them toward the poles (that’s why we have southern lights, or aurora australis, in the southern hemisphere too). When these particles are deflected towards Earth’s poles they interact with our atmosphere, depositing energy and causing the atmosphere to fluoresce.
A 75-year study from retired NASA solar physicist David Hathaway shows that March has more geomagnetically active days than any other month of the year (with October a close second), according to Spaceweather.com. On average, Earth sees six days of high geomagnetic activity in March, compared to just three in December.
Related: Where and when to see the northern lights in 2024
Why does March experience higher geomagnetic activity than any other month?
According to Spaceweather.com, geomagnetic disturbances are almost twice as likely in spring and fall compared to winter and summer due to the Russell-McPherron effect — an explanation proposed in 1973 by geophysicists Christopher Russell and Robert McPherron.
Russell and McPherron determined that the cause lies in how the sun’s and Earth’s respective magnetic fields meet each other. The tilt of Earth’s magnetic field means that in large part, it is misaligned with the sun’s, which causes much of the incoming solar wind to be deflected away from the planet. But during the equinoxes — when day and night are almost the same length due to our planet’s tilt aligning with its orbit around the sun — the orientation of Earth’s poles is almost perpendicular to that of the sun which allows more solar wind to get through, resulting in stronger geomagnetic activity and more dramatic auroras. This year, the vernal equinox (or Spring equinox), occurs on March 19, 2024.
Aurora chasers are already experiencing a great aurora season thanks in large part to the heightened solar activity as we approach solar maximum — the highest rate of solar activity during the sun’s approximately 11-year solar cycle. Solar maximum is predicted to occur from late 2023 to early 2025, making the next few years the best for aurora hunting.
Related: Solar maximum is coming, but we won’t know it happened until 7 months after it’s over
According to Spaceweather.com, March’s geomagnetic activity is already looking promising as experts estimate a CME may graze Earth’s magnetic field late on March 2 which could in turn trigger a minor G1-class geomagnetic storm and spark impressive aurora displays.
So why wait? If you’re thinking of heading on an aurora hunting trip now is the time to do it! March is also a great time to visit Arctic regions as the winter snow is at its deepest and the daylight hours are growing visibly longer. It tends to be warmer and there is less cloud cover at night according to the Aurora Zone. If you want to read more about what it is like to chase auroras in Swedish Lapland, I wrote up a brief account of my recent aurora adventure in Abisko National Park.
We have also rounded up some of the best northern lights webcams so you can keep an eye out for them in the comfort of your own home.
