Space Weather: Sunspots, Solar Flares & Coronal Mass Ejections

Plus Forecasts for Solar Cycle 24 and Cycle 25

September 16, 2018
Space Weather and Solar Flares

Here at the Almanac, we have long believed that solar activity can influence weather patterns here on Earth. Sunspot counts are at an almost 10-year low. Learn more about our Sun—from sunspots to solar flares to coronal mass ejections—and why it all matters.

What is Solar Activity?

First, let’s get to know the Sun. Our burning star may seem like it’s a constant ball, always looking the same. However, just like planet Earth, the Sun has weather. It has storms. And its storms can affect Earth’s weather. Here are few features to know:

  • Sunspots are dark, cool spots on the Sun. Think of them as caps to a magnetic storm that is brewing just below the solar surface. The Sun’s magnetic fields are moving around, getting twisted and concentrated in these regions. Learn more in “What Are Sunspots?”
  • Solar flares appear as flashes of light on the Sun, and are associated with sunspots. Occasionally, when powerful magnetic fields reconnect, they explode and break through the sun’s surface!  There is a sudden burst light energy and X-rays.  Flares are classified according to their strength. The smallest ones are B-class, followed by C, M and X, the largest. M-class flares can cause brief radio blackouts at the poles and minor radiation storms that might endanger astronauts.
  • Coronal mass ejections (CMEs) are massive clouds of particles that spread into space! Large pieces of magnetic energy are hurled from the Sun into interplanetary space at speeds up to several million mph. CMEs can occur when filaments/prominences become unstable and fly away from the Sun. We call this a filament/prominence eruption.
  • Other solar events include solar wind streams that come from the coronal holes on the Sun and solar energetic particles that are primarily released by CMEs.

See the Difference Between Solar Flares and CMEs

What is a Solar Cycle?

Traditionally, the number of sunspots (storms on the Sun) increase and decrease over time in a regular, approximately 11-year cycle, called the solar cycle or sunspot cycle.

Scientists measure solar cycles by keeping track of the number of sunspots appearing on its surface. We are currently in the 24th solar cycle since record-keeping began in 1755. 

The highest number of sunspots in any given cycle is designated “solar maximum.” After some years of high activity, the Sun will ramp down with fewer sunspots or almost no sunspots. When it reaches its lowest number of sunspots, this is designated “solar minimum.”  

As the cycles can overlap, it can be challenging to predict when a new cycle begins. However, there are some clues. For example, sunspots tend to form nearer the equator as the cycle winds down (and at higher latitudes when a new cycle begins). 

Eleven years in the life of the Sun from 1980 (start of solar maximum) to 1986 (near minimum) to 1989 (near maximum again). Credit: NASA

How Does Solar Activity Affect Weather and Earth?

As a technology dependent society, it’s important to know what the Sun is doing.

  • GPS, satellites, and other high-tech systems in space can be caused by an active Sun. Some of these systems are not protected by Earth’s atmospheric layers. So large solar flares have the potential to cause billions of dollars in damage to the world’s high-tech infrastructure—from GPS navigation to power grids to air travel to financial services.
  • Radiation hazards for astronauts can be caused by a quiet Sun. Weak solar winds allow more galactic cosmic rays into the inner solar system. Even airline pilots and crew can get a higher dose of radiation during solar storms.
  • Weather on Earth can also be affected. According to Bob Berman, astronomer for The Old Farmer’s Almanac, NOAA scientists have now concluded that four factors determine global temperatures: carbon dioxide levels, volcanic eruptions, Pacific El Niño pattern, and the Sun’s activity
  • Global climate change including long-term periods of global cold, rainfall, drought, and other weather shifts may also be influenced by solar cycle activity.

The Maunder Minimum or “Little Ice Age” 

Times of depressed solar activity seem to correspond with times of global cold.

For example, between 1645 and 1715—during what we now call the “Maunder Minimum”—there were only about 50 sunspots (instead of the usual 40 to 50 thousand) and harsh winters.

For 70 years, temperatures dropped by 1.8 to 2.7 degrees Fahrenheit.

Painting by Abraham Hondius, “The Frozen Thames, looking Eastwards towards Old London Bridge,” 1677. Image credit: Museum of London.

Conversely, times of increased solar activity have corresponded with global warming. During the 12th and 13th centuries, the Sun was active, and the European climate was quite mild.

When is the Solar Minimum?

We’re currently headed towards a solar minimum, forecasted to arrive in 2019 or 2020 as the Sun switches over from Solar Cycle 24 to Solar Cycle 25. 

During solar minimum, solar flares and CMEs associated with sunspots subside. The Sun’s ultraviolet output dramatically decreases and the upper atmosphere of the planet cools, among other noticeable shifts. Also, we can see the development of longtime coronal holes—vast regions in the Sun’s atmosphere where the magnetic field opens up and allows solar streams to escape the Sun; this can cause space weather effects such as auroras as well as disruptions to communications and navigation systems. At a solar minimum, there can also be less atmospheric friction and “drag,” which could result in more space junk to watch out for.

There is nothing alarming expected; it’s just the normal ebb and flow of the Sun/Earth relationship.

Solar Cycle 24 has been a very quiet cycle, so it’s been difficult to tell exactly when Solar Cycle 25 will arrive. Here’s a very brief history of Solar Cycle 24:

  • Cycle 24 began in early 2008, specifically January 4th.

  • During 2008 and 2009, there were almost NO sunspots, a very unusual situation that had not happened for almost a century. Due to the weak solar activity, galactic cosmic rays were at record levels.

  • In 2010, the Sun’s record-breaking sleep ended. Sunspots started increasing slowly through 2011.

  • In February of 2012, sunspots peaked at 66.9, and then had a lull in activity until late 2013, when numbers began to slowly climb.

  • April of 2014 gave us a second peak at 81.9. Many cycles are double peaked, however, this is the first time the second peak was larger than the first peak (in February 2012).

  • During 2015, monthly sunspots declined steadily to their 50’s. During 2016, monthly sunspot numbers dropped to their 30’s and they just kept going down.

  • In 2017, monthly sunspot numbers declined to their 20’s. 

  • In 2018, sunspot numbers are expected to drop further into the teens. While additional sunspots have appeared (including a massive one in February, 2018), they are increasingly rare as the Sun heads toward the solar minimum. As of August 28, there were 132 spotless days.

  • 2019 and 2020 is expected to bring the solar minimum. It doesn’t mean the Sun goes dormant; the solar activity just changes form, and a new cycle will begin. Stay tuned!

Daily and Monthly Sunspot Numbers


What Does It All Mean?

Overall, quiet-to-average cycles, such as Cycle 24, normally 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.


Want to learn more about weather and space? Pick up your copy of The Old Farmer’s Almanac for this year’s long range weather prediction! Look inside the pages of the latest Almanac.

Reader Comments

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Fraudulent warming, I mean cooling, I mean climate

A little research will reveal that the cooling and warming of the earth is cyclical and the sun is the "main". it is a fact that cooling on Mars occurs with cooling on earth.. No SUV's there that I know of.. It sickens me to see these kids fresh out of college falling for this bunk. Yes, I know, I know 98% of scientist concur, but remember those are only the scientist that someone is asking and 100% of those are getting their funding to provide prove an agenda that man made climate change exist. Find those scientist that don't have to put food on the table from the cause and you'll find the truth whipper snapper. The Young lady who believes the movie "The Day after tomorrow" just makes me embarrassed for her.

Reversal of earth's magnetic fields

Could weak solar minimum cause a shift in earth's magnetic fields?

Solar sunspots

My water well drilling business was directly affected by this solar cycle in the 1980's in Johannesburg South Africa. I began drilling water wells in 1983 as the drought took hold and Southern Africa suffered a terrible drought with crops failing everywhere. I had plenty of work while there were no sunspots and no rain, but when the sunspots returned in 1987, so did the rain and that was the end of my drilling business. The area that I worked in was a summer rainfall area, not like the winter rainfall area around Cape Town. Now with low sunspot activity, the eastern half of the country has enjoyed great rain in the last 2 years, even up until the last 10 days, while the area around Cape Town has had at least 2 years of bad drought. Before the last two years there was a drought on in South Africa in the eastern half in the summer rainfall area up until 2016, which correlated nicely with the droughts every 11 years in South Africa.. Now there is more rainfall. Maybe the weather is saying that the sun spots will soon be returning, even though they are predicted to be absent until 2019/2010.

Chris Landau
Geologist/Meteorologist and amateur astronomer
April 1, 2018 5.45 pm (after April 1st midday cut off time for April Fools day jokes)
I no longer do geology or meteorology but write science fiction and short stories.

Its hot!

The last few years, summers have been relatively mild. But this summer in North CA has been brutally hot! It is 105 right now at 1:30 pm!

Little Ice Age sunspots

How did you come by the number of sunspots during this time period? Thanks

solar activity

Have I a correlation between less solar flares and the weather being colder in America and England.The cold air pushing down from Canada and Russia.slightly counterclockwise?

There were many scientists

The Editors's picture

There were many scientists who studied the Sun’s energy output though there weren’t official records. British astronomer John Herschel (1792–1871) and French physicist Claude Pouillet (1790–1868) were some of the first who invented apparatus for measurements.

sun observtions

The article states that record keeping began in 1755. So how do you know how active the sun was in the dates you mention that came before 1755. Especially for the 12th and 13th centuries?

what is the difference

what is the difference between Coronal mass , solar flaire and sunspots?

solar definitions

Please see the article above for a brief description of each. The sun is made of gases that rotate, generating magnetic field - but various sections rotate differently. Hot gases bubble and burst through the mix, tangling and looping the “lines” of the magnetic field. Sunspots, which appear to us as dark patches, are magnetic storms on the surface. They occur where these intense magnetic loops poke through the Sun’s surface. Eventually, like an overstretched rubber band, each stressed magnetic field “breaks,” releasing tremendous energy and magnetically charged gases into space. Solar flares are bursts of radiation released, including visible light and x-rays. A solar flare from the Sun can reach Earth in about 8 minutes, and can last from a few minutes to several hours. Their strength is rated according to their brightness in x-ray wavelengths. Coronal mass ejection, or CMEs, are large clouds of gases and magnetized particles (plasma) thrown out from the Sun; if oriented in the proper direction, a CME can take 1 to 3 days to reach Earth. Flares and CMEs can occur at the same time, but not always. Solar flares are localized, usually occurring near a sunspot; CMEs are much larger events, and can sometimes be larger than the Sun. Both flares and CMEs, depending on strength and orientation, etc., have the potential to disrupt communication signals (satellites, radio, etc.) and cause power grid fluctuations. Both solar flares and CMEs can cause auroras.


I got more knowledge about in the solar cycle activity.

Just read your reply to my

Just read your reply to my earlier submission on solar cycle 24. However, you were silent on a question I posed: Any geophysical explanation for the existence of more or less, two distinct pronounced peaks during this cycle. An explanation, if any, would be appreciated.

I wonder why solar cycle 24

I wonder why solar cycle 24 reached its maximum in 2014, to me that was delayed by roughly two years. The peak was expected by 2012! Or, were there two peaks in this cycle? Any explanation(s) please?

Cycle peaks

Hi, Larry,

Sunspot cycle duration is 11 years on average and typically peak, one time, in the middle of that period. Not all cycles are the same, however. Solar Cycle 24 is now well into its declining phase after reaching double peaks in late 2011 and early 2014. Despite having two maxima, this cycle is the smallest in more than 100 years, and solar activity is expected to continue to decline from these low peaks toward its expected minima in early 2019.

For a glance at Cycle 25, click here:

Sunspot cycle and global climate

Since the lions share of energy that warms the earth comes from the sun any reduction of solar out put will cool the earth regardless of what we people do or don't do. The best thing mankind could do is get set for a moor glaciation and that includes having contingency plans for relocating nuclear fuels, waste and power stations in short order.

Very clear the explanations.

Very clear the explanations. Congratulations.

Solar Radiatons

I want to know about that

Dear Friends, Can someone

Dear Friends,

Can someone tell me what the pre-dawn northern California sky would have looked like the morning of the April 18, 1906 SF earthquake?

Was Mars unusually visible, or would there have been something else interesting in the sky?

Following a weak solar cycle, had there been a notable cooling phase?

I'd love to know anything specific. Thank you, Robin

Hi Robin,

The Editors's picture

Hi Robin,

According to our 1906 Old Farmer’s Almanac, Mars was an evening star until July 15, then it became a morning star for the rest of the year. The right-hand page for April 1906 says “Low tides” for April 18. The day before (April 17) Mercury was stationary. On the 19th, there was a conjunction of Saturn and the Moon. Last quarter Moon was on April 15 (ET). Moon runs high was on April 2; Moon runs low was on April 13. Moon at perigee on April 10; Moon at apogee on April 25. Hope this helps!

I recently came across the

I recently came across the book "Dark Winter" by John L Casey.
This book defines not only the short but the long (206 yr) cycle.
These cycles are interesting to me personalty as their results are outlined by my grandfathers as far back as the late 1600s.
I have a practical question: What will be the impact on solar panel power production as the result of a Solar Minimum?

Im thinking, by observing the

Im thinking, by observing the severity of the weather where im at, i noticed, we seem to have more intense whether patterns when a significant cme has made impact with earth

There is a distinct

There is a distinct possibility that as Uranium is used up, the geomagnetic forces are being disrupted and sulfuric acid and/or phosphoric acid is splattering about the sun mainly composed of glass.

Thus, Uranium use must be reviewed in this light all around the world.

I'm not sure where you got

I'm not sure where you got your Ph.D.

The Sun is not burning uranium. It's burning Hydrogen, converting it to Helium through the fusion process.

Elements stratify by density

Elements stratify by density and if what is known on earth is applied to the sun then an assumption can be made that the lightest known elements will be on the outer surface of a celestial body and the densest at its core. Uranium and other radioactive matter are the denser elements known to man, and hydrogen is the least dense so it would make sense that the sun has a super dense radioactive core and a foamy hydrogen surface. "Science" makes conclusions about the Sun based on what radiometric spectra its surface emits... Sadly this reasoning is as profound as if one were peering down on Earth through a space telescope and determining the engine under the hood of a parked car based on the color of its paint. All that to say there may be some substance to what Mr PHD has stated.

Electrical Universe

I'm not saying Dr. Uranium is correct but you referenced hydrogen and fusion in your theory what state do you propose the hydrogen is in before and after this fusion process??

I have always believed that

I have always believed that the activity of the sun is the primary driver of our weather. Blaming CO@ is truly a scam. It is only 400 PPM overall in our atmosphere. What we do not hear is how much is man-made. Scientists tell us it is 3% of the 400 PPM. The ocean absorbs about 40% of that so that leave us with our part being 1.8%. That 1.8% of man's part is globally. Now USA only accounts for 3% of the entire globe. That means our part in the USA has to be extremely minute. Somewhere around .0005% of man=made CO2. Dang. Did you know that the biggest polluters are China and India and they are exempt from Kyoto? It would cost us billions to correct our part by only 10%. To get an additional 10% it would cost us twice as much as the 1st 10%. We cannot afford that and we wouldn't make any measurable impact on global warming at all.We are wasting our time. And by the way, the recommended level for all plant life is between 1000 and 1500 PPM of CO2 which has been proven by 1000s of studies paid for by our government. We need more CO2, not less. Marijuana growers use a level of 1200 to 1500 PPM for ideal marijuana growing in a greenhouse.The ones who push global warming are the ones who smoke the most of this weed. And they want it perfectly grown, of course. I will be so glad when the mini ice age gets here. They will have to smoke in doors and create a lot of carbon monoxide. And that would be a good thing in this case.

I like how they break it down

I like how they break it down and show some examples.

Nasa and NoAA who have been

Nasa and NoAA who have been involved in changing temp readings that are now under review. You want us to believe them. Really.

No way is the carbon 13/12

No way is the carbon 13/12 ration a scam. The upper layers of the atmosphere are not showing enough heat content to point to solar activity as a major source of climate disruption. PLEASE read the NASA and IPCC reports. Forced global warming is real.

With the earth's continual

With the earth's continual global warming I believe the movie "The Day After Tommorrow" is in line with what is actually occurring now! The oceon is getting warmer and warmer and it is the barameter of our weather and if it is effected much more it will certainly trigger a mini ice age which the earth did have several hundred years ago for about 500 years that killed a lot of people.