Solar Cycle 25 is official under way as of September, 2020. Following a weak Solar Cycle 24, what do we expect from the Sun moving forward? Learn more about predictions regarding the next solar cycle.
The Old Farmer’s Almanac pays attention to solar science as it’s one of the disciplines employed in the making of our long-range weather predictions. Our founder, Robert B. Thomas, who started this almanac back in 1792, weather on Earth was influenced by sunspots, which are magnetic storms on the surface of the Sun. See how The Old Farmer’s Almanac predicts the weather.
Solar Cycle 25 Has Begun
Solar Cycle 25 in now underway, as NASA and NOAA announced on September 15, 2020. This means that our star, the Sun, has passed from one of its 11-year activity cycles into another.
Solar cycles typically occur in 11-year periods (but can range from eight to 14 years). In a solar cycle, there is a “minimum” when the Sun is least active and a “maximum” when the Sun is the most active. What are solar cycles? Learn more here.
Solar Cycle 24 lasted 11 years, which is average, though it was the weakest cycle in 100 years. As Solar Cycle 25 begins, we are coming out of the minimum or bottom of the cycles—which happened in December 2019 when the sunspot numbers fell to its lowest in 13 month (with sunspots at only 1.8). Solar maximum occurred in April 2014 with sunspots peaking at 114 for the solar cycle, well below average, which is 179.
Solar Cycle 25 Predictions
Since December 2019, sunspot counts have been steadily increasing, though slowly. This pace, along with other indicators, suggests that Solar Cycle 25 (like Solar Cycle 24 before it) will be one of the weakest since record-keeping began in 1755.
According to NOAA/NASA and international experts: “Cycle 25 will be similar in size to Cycle 24, preceded by a long, deep minimum. Solar Cycle 25 may have a slow start, but is anticipated to peak with solar maximum occurring between 2023 and 2026, and a sunspot range of 95 to 130. This is well below the average number of sunspots, which typically ranges from 140 to 220 sunspots per solar cycle.”
- Specifically, the experts predicted: a peak in July, 2025 (+/- 8 months), with a smoothed sunspot number (SSN) of 115.
- The panel agreed that Cycle 25 will be average in intensity and similar to Cycle 24, and its peak will be similar as well.
- Additionally, the panel concurred that solar minimum between Cycles 24 and 25 will occur in April, 2020 (+/- 6 months).
In othr words, expect the rest of 2020 to be very quiet with low solar activity. This is not to say there won’t be some solar storms, but it should be relatively uneventful.
Solar Cycle 24 Recap
Solar Cycle 24 was one of the quietest, weakest cycles in a century. (The prior cycle, 23, also had an extended period of very few sunspots.)
For posterity, below is the very brief history of Cycle 24, which we were watching since it began in December of 2008—two years later than expected.
Spotless Days (through September 16, 2020)
2020 total: 181 days (70%)
2019 total: 281 days (77%)
2018 total: 221 days (61%)
2017 total: 104 days (28%)
2016 total: 32 days (9%)
2015 total: 0 days (0%)
2014 total: 1 day (<1%)
2013 total: 0 days (0%)
2012 total: 0 days (0%)
2011 total: 2 days (<1%)
2010 total: 51 days (14%)
2009 total: 260 days (71%)
2008 total: 268 days (73%)
2007 total: 152 days (42%)
2006 total: 70 days (19%)
Brief History and Highlights of Cycle 24
Cycle 24 began in early 2008, specifically on January 4.
In 2011, sunspots started to build again. A monthly spike occurred in November 2011.
In early 2012, the smoothed sunspot number reached a first peak of 98.3 (March, 2012).
But April 2014 brought a second peak. The smoothed sunspot number reached a second peak of 116.4 (April, 2014). This became the official maximum. It’s not unusual to have a double peak, but it’s rare that the second peak is larger than the first. Cycle 24’s peak still ranks as the weakest since Cycle 14, which peaked in 1906.
From 2015 to 2017, sunspots kept dropping steadily from 0% spotless days in 2015 to 28% spotless days in 2017.
In 2018, 61% of the days were spotless! We went weeks at a time without a single spot on the Sun’s face.
In 2019, even more days were spotless (77%), hitting rock bottom in December.
In 2020, sunspot counts were at their lowest at the start of year but started to pick up slowly.
Prospects of a Mini Ice Age
What do inactive solar cycles mean in terms of climate and weather? Overall, quiet-to-average solar cycles with deep solar minimums mean a cooling pattern. In other words, temperatures become colder than they would have been otherwise. Sunspots are similar to a bathtub of lukewarm water; if you trickle in cold or hot water, it may take a while to notice the difference.
If this cooling phase on Earth, however, is offset by any warming caused by increasing greenhouse gases, it also raises the question of whether an eventual warming cycle could lead to more rapid warming on Earth than expected.
Could a deep, long-lasting solar minimum lead to extreme cold such as a mini ice age? In the 17th century, the 70-year Maunder Minimum brought a very cold period to the Earth.
- According to solar radiation expert Judith Lean, PhD, of the Naval Research Laboratory, if we do have a “Maunder Minimum,” it would not be a return to the “Little Ice Age.”
- She points to a current global surface temperature that’s about 1.8 degrees Fahrenheit warmer than at the time of the Maunder Minimum and says that a return to a Maunder Minimum phenomenon would lead to a cooling by only one-tenth of a degree C or 0.18 degree F.
Also, Lisa Upton, Ph.D., solar physicist with Space Systems Research Corp., states that “the expectation that Cycle 25 will be comparable in size to Cycle 24 means that the steady decline in solar cycle amplitude, seen from cycles 21 to 24, has come to an end and that there is no indication that we are currently approaching a Maunder-type minimum in solar activity.”
In other words, the occurrence of a new mini ice age is doubtful.
Much of this is the normal ebb and flow of the Sun/Earth relationship, which can be stormy. That said, if the Sun goes through a more prolonged solar minimum, then Earth could experience a cooler period.
One of the bright sides of solar cycles is the Northern Lights! We’re looking forward to an excellent season for aurora watching! Learn more about what causes the Northern Lights.
Stay tuned for further updates! Want to learn more about weather and space? Pick up your copy of The Old Farmer’s Almanac!