They were peering over their balconies, huddled at the top of lookouts or drinking coffee, eyes turned to the sky for a hint of color — any color.
As night fell, chasers of the aurora borealis in the northern hemisphere on Friday were out again. The vivid hues, which are most often seen closer to the North Pole, lit up skies in an unusual showing in the lower latitudes of Europe and North America last week.
Those who missed the lights, or who were eager to see another showing, set their alarms and monitored aurora watch apps, hopeful for another opportunity. Some people in Canada and Britain said they were rewarded, while others in the northern United States kept a watchful eye on forecasts.
But predicting when an aurora will show up can be tricky, forecasters said, given that sun activity during its cycle is constantly evolving.
“Broadly speaking, though, we do know that activity and sunspot numbers should increase in this part of the cycle,” Tom Morgan, a meteorologist for the Met Office, said.
At least for this weekend, aurora sightings in the United Kingdom are unlikely, according to the Met Office, though there is a “slight chance” that the lights may appear in northern Scotland before sunrise on Sunday.
The northern lights could return on Monday over Scotland and Northern Ireland, and there is a chance they could be visible to the naked eye in northern England and Wales. Monday is expected to be clear, with some showers.
Seeing the northern lights, seasoned chasers say, takes planning, patience and a group effort.
“We set up a small aurora group in my little village,” said Steve Emery, 50, who lives in the village of Hesket Newmarket in northwest England. He said that a group of about 20 people had been chatting about the forecast.
“It’s kind of become a local hobby, which is quite fun,” he said.
Mr. Emery was sitting in bed when alerts pinged at 1 a.m. that the northern lights might be visible. He and others in a chat group rushed in their cars to the top of a nearby hill.
“They were faint but you could definitely see the greens, particularly, and the purples,” he said. “They were shimmering as well.”
Mr. Emery, 50, said that the movement of the lights reminded him of closed curtains swaying at the end of a theater show. Within five minutes, he said, they had come and gone.
“It happens so quick, you need to be ready for it,” he said, adding that the colors are different each time. “You never know quite what you’re going to see. That’s the addictive nature of it.”
Others, even with preparation, were foiled by light pollution, a bright moon or clouds.
Had they glimpsed the aurora, or was it simply nearby light pollution? (That unique disappointment was captured in a TikTok video when two friends in Norwich shared that the purple glow of what they had thought was the aurora borealis was, in fact, the light coming from a Premier Inn.)
The solar storms are caused by an interaction of light particles with Earth’s magnetic field, and auroras are brighter and farther from the poles when geomagnetic activity is high. The sun typically goes through an 11-year cycle of activity, and when activity is high, it is known as solar maximum.
The display last week came after the National Oceanic and Atmospheric Administration issued a rare warning on May 10 that a Level 5 solar storm had reached Earth — an extreme event not recorded since October 2003.
Seasoned chasers and experts have a few tips: Get away from the city lights. Go to a vantage point with clear views, like the top of a hill. Look north. And use your cellphone to take photos since it can pick up more wavelengths than the naked eye.
In Norway, Cathe Sletaker was getting ready for bed in her home in Hole, about an hour northwest of Oslo, when she got an alert. She went onto her balcony.
The sky was light, but she caught a pale showing of purple, lilac and green lights.
“I stayed there until 3 o’clock in the morning,” she said. “My cat visited me, too, and I took a nice picture of her.”
The lights, she said, were not as strong as the spectacle last week, but Ms. Sletaker still felt a tingle.
“I get the feeling — perhaps it’s a bit big to say — of the universe; everything comes a bit close from outer space,” she said, adding, “It’s a kind of magic.”
