When did solar cycle 25 start, and when will it end?
Catherine Boeckmann
February 24, 2023
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The Sun is now in Solar Cycle 25, which is heating up more than experts predicted! Learn more about when Solar Cycle 25 started, when the cycle is predicted to end, and sunspot activity through January 2023—which just hit a 9-year high!
Solar Science and the Weather
Why are we reporting on solar cycles? 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. See how The Old Farmer’s Almanac predicts the weather.
Our founder, Robert B. Thomas, who started this almanac back in 1792, believed that weather on Earth was influenced by the cooling and warming of the Sun, as evidenced by sunspot counts. Sunspots are fiery storms on the surface of the Sun. Learn more about sunspots.
Solar Cycle 25
We’ve now entered Solar Cycle 25, which is the 25th cycle of the Sun since record-keeping began in 1755.
Over the years of observing the Sun, we’ve learned that the Sun goes through warming and cooling cycles of about 11 years—which affects weather here on Earth.
When one 11-year solar cycle transitions to another, it starts quietly with low solar activity (called a “solar minimum”). Then the Sun’s activity builds up to the cycle’s peak (called a “solar maximum”) when its magnetic field reverses. Finally, the Sun settles back down to a minimum before another cycle begins.
When Did Solar Cycle 25 Start?
According to NOAA/NASA, the new Solar Cycle 25 began in December of 2019. This was based on detailed records of the number of sunspots and solar cycle activity, as the 13-month smoothed sunspot number fell to 1.8. Leading up to this month, the Sun showed signs that its poles were going to reverse magnetic polarity; in November 2019, two reversed polarity sunspots appeared. Learn more about solar cycles.
When Will Solar Cycle 25 End?
Solar Cycle 25 is predicted to continue until 2030, with peak sunspot activity expected in 2025, according to the NASA/NOAA panel of solar science expert.
Solar Cycle 25 Predictions
The experts predict a weak solar cycle 25—below average, quiet, and cool. This is very similar to its predecessor Solar Cycle 24, which was one of the quietest, weakest cycles in a century. (The prior cycle, 23, also had an extended period of very few sunspots.)
According to NOAA/NASA and international experts: “Cycle 25 will be similar in size to Cycle 24. 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 range from 140 to 220 sunspots per solar cycle.”
Specifically, the experts predicted a peak in July, 2025(+/- 8 months), with a smoothed maximum sunspot number of 115 to 120 for cycle 25. 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).Â
Solar 25 Predictions Update (January 2023)
The Sun is in the rising part of its 11-year cycle of activity. Surprisingly, Solar Cycle 25 heated up more quickly than expected! As at Jan 20, 2023, solar cycle 25 is proving to be bigger than solar cycle 24, with +12% daily sunspots for solar 25 versus same point in cycle 24 (Jan 20, 2012).
2020: Late May saw the first C-class solar flares, which picked up in the autumn, with a spike in October, leading many experts to wonder if solar cycle 25 was going to be more active than predicted. Total days without sunspots was 57%.
(Note: C-class flares are smaller flares; M-class flares are moderate; X-class flares are strong.)
2021: Solar activity in spring quieted down and then July bought the first strong X-class solar flare of the cycle, as well as more solar activity across the Sun’s disk. October bright more activity with an M-class and a second X-class flare. November peaked with the strongest geomagnetic storm to hit Earth since September 2017. Total days without sunspots was only 18%.
2022: Against consistently stronger base of solar activity and C-class flares all year, 2022 saw a flurry of M-class and X-class flares in March and April, with some of the strongest flares of the cycle to date. Total days without sunspots dropped to less than 1%.
2023: January started out with a 9-year high. The month had 144 monthly sunspots (0 days without sunspots), very close topping the Solar Cycle 24 which hit a monthly value of 146 in February 2014.
The chart below shows how the monthly sunspot number skyrocketed in January 2023.
A major X-class solar flare erupted from the Sun over Valentine’s Day week, causing a radio blackout for parts of Earth and setting the stage for more flares to come. Strong X-class flares also lead to coronal mass ejections (CMEs), ejecting solar plasma into space; when spewed toward Earth, CMEs can interfere with communications systems, power stations, and satellites in space.Â
So, what do solar cycles mean in terms of climate and weather? Overall, history has shown us that 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.
 Aurora photo taken by Andrei Andritcu on January 9, 2022 in Tromsø Norway.
Real Immediate Effects of Solar Activity
As Solar Cycle 25 builds, strong solar storms are more likely to erupt, boosting the potential for both possible disruptions with satellites, radio communication, and power systems.Â
This is a very real threat. In early February 2022, a geomagnetic (solar) storm destroyed 40 new SpaceX satellites in orbit. With the thousands of small satellites now in orbit which provide all of us with internet service and other communications, solar activity needs to be taken seriously.
Image:Â The TIMED satellite monitoring the temperature of the upper atmosphere.
On the bright side, more solar activity lends itself to more awesome displays of the bright auroras!Â
An excellent article save for "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."
Greenhouse gases do NOT alter climate. Such claims are based on assumptions, not science. The observed evidence is very clear as well-documented in "Looking Out The Window" (Nov. 2021). Based on geologic, ice core, and contemporary records, CO2 and global average surface temperature (GAST) are uncorrelated over every meaningful timeframe of the past half-billion years. No correlation means no causation possible.
When Earth's atmospheric CO2 reached 150 ppm, the incremental increase in GAST caused by increasing atmospheric CO2 became so trivial as to be unworthy of consideration as a climate change force. Policies based on fiction will lead to no good. It is time to put the invalid theory advocated by the UN-IPCC in the rubbish heap of every other invalid theory.
Highly credentialed leading scientists not funded by climate change activists in government provide the irrefutable science that shows current or future contributions from incremental increases of both atmospheric CO2 and CH4 to changing GAST are so trivial as to be meaningless.
It's time to stop giving an incredible theory any credibility by routinely referring to "increasing greenhouse gases" as a meaningful climate change force.
All the proof one needs is found by just "Looking Out The Window".
A good article up to the point when you claim CO2 causes warming. Not one scientist has proven that CO2 causes warming. The level of CO2 during the last ice age was 100 times higher than now.
CO2 levels are historically very low.
I wonder if some years we have "open" winters without much snow then in a few years we have snow up to our shoulders,, is result of the sun's cycles???
It seems odd to conclude that the earth should get even warmer as the current solar minimum ends. The fact is that sunspot activity is at a low right now and it would seem the logical conclusion would be a colder winter.
Thomas, you are right about low sunspot activity being associated with cooler temperatures. However, there are other mitigating factors (CO2 is NOT one of them as it isn't a meaningful factor at all). Lower sunspot numbers mean less "solar wind" that disrupts cosmic rays. Cosmic rays are known to "seed" clouds in the atmosphere (provide something for water vapor to condense around forming water droplets which accumulate to clouds). More cloud cover means cooler temperatures. So there is a definite link. However, the atmospheric steering currents (PDO, NAO, etc.) are influenced by ENSO cycles which, in turn, may reflect geologic activity in the western Pacific. We're in a changeable ENSO pattern, so early, mid, and late winter may be mild in one area, cold in others and change during the season. Despite all the baseless thunder from the UN-IPCC, weather and climate are far too complex for any scientist to be able to predict with certainty what the future holds. We can only generalize based on typical circumstances. The same reason weathermen have less than perfect accuracy. So in general, solar minima produce cooler climate whild solar maxima produce warmer climate, but not every year. Hope this helps.
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