What Are Solar Cycles, and How Do They Affect Weather?

Learn About the Sun and Its Effect on Earth's Climate

March 4, 2021
Space Weather and Solar Flares

What are solar cycles and sunspots—and what causes them? Here at The Old Farmer’s Almanac, we believe that all weather on Earth, from the surface of the planet out into space, begins with the Sun. Here’s our quick solar cycle beginner’s guide to help you understand the basics of how our Sun’s 11-year solar cycle works.

Both space weather and terrestrial (Earth) weather—the weather we feel at the surface—are influenced by the small changes the Sun undergoes during its solar cycle.

What is the Solar Cycle?

The simpliest solar cycle definition is: “The solar cycle is the cycle that the Sun’s magnetic field goes through approximately every 11 years.”

Let’s explain: Remember that the Sun is a hot ball of glowing, electrically-charged gases. The Sun’s high temperatures causes these electrically-charged gases to constantly move around, generating areas of powerful magnetic forces or fields. This motion creates a lot of activity on the Sun’s surface, called solar activity.

In areas where the magnetic fields are particularly strong, we may see a black spot—called a sunspot—emerge on the surface of the Sun. This is indicative of a sunstorm and a lot of activity beneath the surface. More sunspots means more solar activity.

There does seem to be an ebb and flow or “cycle” to this magnetic flow and movement. The total number of sunspots has long been known to vary with an approximately 11-year repetition known as the solar cycle—going from low to high and then high to low. The peak of sunspot activity is known as solar maximum and the low is known as solar minimum.

Note: The exact length of the cycle is not always 11 years; it has been as short as eight years and as long as 14.

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

Sunstorms, Flare-Ups, and Eruptions!

Our burning star may seem like it’s a constant, unchanging ball, always looking the same. However, just like planet Earth, the Sun has weather. It has giant storms! It flares up! It ejects huge bubbles of gas from the surface toward space and our planet. Here are some definitions: 

  • Sunspots indicate active magnetic fields. The dark spots are cooler than the surrounding areas. 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.

Solar flares, CMEs, and other explosions tend to occur near sunspot groups when the Sun is more active. Naturally, all of this solar activity coincide with solar maximum.

Watch solar flares versus CMEs

Why Does the Solar Cycle Happen?

The Sun goes through these cycles due to its magnetic nature. The Sun itself has a north and a south magnetic pole.

Because the Sun’s gases are constantly moving, the magnetic materials constantly gets tangled, stretched, and twisted. Over time, these movements eventually lead to the poles reversing.

The solar cycle happens because of this pole flip! The north becomes south and south becomes north every 11 years or so.

The poles reverse again back to where they started, making the full solar cycle a 22-year phenomenon. 

How Does Solar Activity Affect Weather?

The Sun affects both weather and technology (which we’re increasingly dependent on) here on Earth. For example:

  • GPS, satellites, and other high-tech systems in space can be affected 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.

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

The Maunder Minimum and the “Little Ice Age” 

Times of depressed solar activity seem to correspond with times of global cold in history. The most famous example is the “Little Ice Age.”

  • Between 1645 and 1715—during what we now call the “Maunder Minimum”—sunspots were exceedingly rare.
  • Specifically, 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. 
  • Seven decades of freezing weather, corresponding with the coldest period of the Little Ice Age, led to shorter seasons and ultimately food shortages.

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.

Experts do not know for certain, however, what caused the Little Ice Age; theories suggest that it was likely due to a combination of events. Some scientists are researching other factors, such as heightened volcanic activity, that corresponded with the time of the Maunder Minimum.

What Solar Cycle Are We In Now?

We are now in Solar Cycle 25. Record-keeping of solar cycles began in 1755 with Solar Cycle 1. 

In December, 2019, the sunspot numbers hit the solar minimum and “rock bottom” and the Sun passed from Cycle 24 into Cycle 25. The solar maximum or peak is predicted to happen in July, 2025.

  • By solar minimum, we mean the lowest number of sunspots. After some years of high activity, the Sun will ramp down with fewer sunspots or almost no sunspots. The temperature cools.
  • Conversely, solar maximum is the highest number of sunspots in any given cycle. A new cycle starts with a “solar maximum” littered with solar storms and sunspots. The temperature warms.

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 Sun’s equator as the cycle winds down (and at higher latitudes when a new cycle begins). Scientists measure solar cycles by keeping track of the number of sunspots appearing on the Sun’s surface as well as noting the location. A new solar cycle is considered to have begun when sunspots group at higher latitudes with the magnetic polarities of the leading spots opposite that of the previous cycle. 

Will Solar Cycle 25 be quiet or wild? See the predictions for Solar Cycle 25.


Reader Comments

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Very good article. Global

Very good article. Global warming it's a big scam.

No... Global warming is not a

No... Global warming is not a 'big scam' - imho, the accepted view is incorrect in some important areas, but generally we are seeing a change in the global climate towards warmer temperatures, and this article does not imply that either. If you read carefully you will see it say that climate change has been 'mitigated' by the temporary low output from the sun and has 'bought us time'.
In fact I think looking at the very cool summer of 2013, it has done more than offset the slight warming due to climate change, it has started to switch into a mini ice age similar to Maunder minimum - I am quite happy for my name to be used to describe the 2013 "Robinson minimum" if you like :)

I believe that there is a latency of around a year in the Earth's atmosphere which means that normally we don't even feel the effect, but due to the last quite weak maximum, and the last extended minimum, we are feeling a very cold summer across all of the northern hemisphere. I live in the southern hemisphere, and I can assure you the effect is global, our winter is starting out very cool also.

You have failed to

You have failed to realize/recall from high school science. The weather is driven by the sun. Daily weather by the sun. This has been known for decades, I heard it as matter of fact in the 60s. Extremes in weather are driven by Solar flares and sunspot activities. If you do a little more study, you will learn that the 3.7/10,000 ppm of CO2 actually reflects more harmful solar radiation than is reflected back in the narrow spectrum of infra red relfected back. This was identified and proven around 1900. In fact, they proved over a 100 years ago that the CO2 100% reflection of this narrow band of infra red is reflected back at 25% concentration. That increasing the concentration does not change the energy level. You cannot reflect back more than 100%... Thus the premise that increasing CO2 would increase global temps. The admitted to .9deg F over the last 100 yrs does cannot be argued is a result of CO2 elevation.
Another interesting fact, many of the scientist from varying backgrounds who originally signed onto the global warming theory have apologized and now assert the theory was poorly based. Even this year, the original NASA scientist that proposed this "theory" has now been peer reviewed by NASA scientist that his data was faulty and conclusion as well. They also were the ones that said this low level of CO2 was responsible for reflecting harmful radiation, similar to what the Ozone does. There too often is more. NPR is not a good resource... other than vague siting of exaggerated assertions

Dear "You have failed

Dear "You have failed to":
Question: How does an optically clear gas like CO2 relect light? We know that it absorbs infra-red light in the mid IR at about 2200 cm-1. This is a narrow and intense absorption peak. It probably absorbs in the UV because is has sigma and pi bonded electrons (4 each) in the C=O double bonds. It also has 8 non-bonding electrons (4 on each oxygen). These have excited states that require energy from light in the UV region of the spectra. (I am not familiar with its near or far IR spectra) However, it is optically clear to visible light. CO2 does not reflect light. (If I am wrong, please provide the mechanism) However, it can absorb and re-emit UV light as the excited electrons drop back down to the ground state (this is certainly not reflection). This, however, is not true of IR frequencies. Since IR electromagnetic radiation causes polar bonds to vibrate the energy is discipated and not re-emitted. That is why in IR, one can talk about transmitance and absorbance, but never emission spectra.
Lastly, ozone does not reflect any light either. It aborbs UV light in the process of undergoing a multi-step chain reaction cycle called the Chapman Cycle. This energy is used as activation energy in the process.

maybe global warming as a

maybe global warming as a result of CO2 is a scam after all!!

new NASA research says CO2 is a global COOLER, reflecting more solar energy during the day than it retains at night


Rev. 16:8,9 says That the Sun

Rev. 16:8,9 says That the Sun will flare up and scorch the earth. I have read the Bible over the past 40 years and it does have astronomical data that is exact and correct, as they have the history of the mesopotamians and babylonians early observations of everything that moved in the heavens and there timing ect... so as also these luner eclipses as recent as today which are being called bloodmoons! Or the so called star that moved over where Jesus was born and the wise men who saw the sign or star of the king to be born! I find this a frightening thing to here scientists say they expect a possible direct hit on the earth with a solar flare, It would destroy the power grid and I can't even count the numerus technologies effected ! mankind would suffer and all living things for that matter!Like in the movie terminator sarah conner says youll need a sun tan lotion with a uv protection of 10 million ! I do have a question for anyone reading this . If there was a solar flare to hit earth would it heat the earth ? and if so but how many degrees ? and could it cause the ocean to steam and make a cannopy of clouds ? and would thoese clouds cool the earth?and would it become darker and cause less food to grow? NOHOMEHERE



If we understand solar cycles

If we understand solar cycles ultimately determine weather and there is a possible coming mini ice age is a "carbon tax" advisable for any reason other than political?

I love the great info

I love the great info here..thank you orbs of light. Wax and wane cycles flow in conformity to all involved..where is the wax and wane of sirius a&b above?..have we passed the harmful radiation of that stellar dog encounter..or is its fifty year switching creating seventy year wobbles in our zone

I wanted to see actual

I wanted to see actual pictures of sunspot activity before, during and after the Earthquake in Japan last April, 2012. Is their a site ? I've googled similar questions.

To see sunspots and other

The Editors's picture

To see sunspots and other solar activity on a certain day, or range of days, you might try the following site from NASA's Solar Dynamics Observatory:


Input the date range that you'd like to see. Select the type of instrument, such as the "HMI Intensitygram (orange)," the "AIA 171 (gold)," or the "Composite AIA 171, HMI Magnetogram." Click submit. You will get a movie of all images for your range, showing sun activity.

You might also be interested in our article on sunspots:


Hope this helps!

i have for many years gone to

i have for many years gone to space weather and the earthquake and volcano usgs real time maps...i was watching have been, and still am. i can't see a connection on the number of spots, the solar wind speed is always high when the quakes happen. maybe a earth reaction to the suns encounter with our atmosphere.

Has anyone produced a chart

Has anyone produced a chart of solar cycles that parallels weather trends in the central United States? I thought I had heard of such a thing but haven't found it.

So are these solar flares at

So are these solar flares at their peak in 2012? I wonder if that is related to the Myans? So we are in our second year of drought NE Ok, is the drought related to the solar flares Xstorms? Because I am very tired of the drought I am a farmer Thanks

sunspots are supports to peak

sunspots are supports to peak 2013?

I regard the solar cycle 24

I regard the solar cycle 24 is weak in terms of sunspots only. It is these that give us the extra UV and X-rays which affect climate. Of course, it may not be weaker in some other less important respects.

How can you possibly say that

How can you possibly say that the solar cycle is weak? You report on the X flares (3), and fact that there has been 0 sun spotless days in'12 , or that people who live in high lat. say they have never seen such active and continuous auroras should convince you. also I live in MI and it has been the warmest, no snow, I can ever remember(not over yet I know). But if you still must convince yourself I have hard evidence. Just visit the solar dynamics observatory website-they have a cool tool-under the 'data' heading go to access more data then go to*LMSAL iSolsearch* you can use the tool to research any day or span of days to see all kinds of different data regarding the sun. Just compare Nov 2011-now with 2000-01, you will clearly see how cool this tool is and I hope in the April update you do not say WEAK!!!!

Our reports come from NASA,

The Editors's picture

Our reports come from NASA, NOAA, and SDO. Thus far, March has certainly been active with Sunspot AR1429. This makes sense as the next solar maximum is expected in the 2013-2014 time frame. In terms of the overall cycle, NASA experts believe it will be a "below-average cycle" with less than your historically normal number of sunspots. However, you are correct in saying that "weak" is not an accurate description. Even a below-average cycle is capable of producing severe space weather.

The sunspot numbers are 1/2

The sunspot numbers are 1/2 of those from a normal cycle. An extended cycle is also a very weak one. Similarly, the solar zonal flow for cycle 25 has yet to appear. This means a very long cycle 24.

The sunspots are much shorter

The sunspots are much shorter in duration. Normally, sunspots last about 30 days. This cycle, they seem to last about 3 days. So, it is a much weaker cycle. This does not mean that the solar flares are weaker, just the overall sunspot count and duration. Much weaker than the previous cycles. Don't seem to hear much about this aspect of it.

This solar cycle has actually

This solar cycle has actually been historically weak. While the sunspot counts may be good data for certain aspects or heliophysics, when it comes to actual activity coming from these regions, solar cycle 24 shares more in common with the Maunder Minimum than more active periods, as during the 1940's. The Maunder Minimum is named for the scientist who was observing it's onset - which began with sunspots diminishing and vanishing as they rotated to the earth-facing side of the solar disk. This has been the major feature of this cycle as well - no large, magnetically complex sunspot has made much noise on the earth side of the disk.

Now, the still-theoretical science studying how this affects weather is one of the most fascinating subjects there is -- it will make you think of the earth and the sun and their connection in a much different way. When we have weak solar activity with no strong flaring, the earth is being bombarded with fast solar wind from coronal hole streams, and our atmospher at all layers experiences a pushback -- quite literally, it shrinks, and the tension between layers leads to unusual phenomena. Closest to the ground, where the troposphere and statosphere are being pushed, the tops of thunderheads emit types of lightning called sprites, elves, fairies; which reveal a jellyfish-resembling network of glowing red/blue electric plasma high in the sky. They are truly an ominous sight, as are undulatus asperatus clouds - cloud formations that look like rough waves in an upside down sea of grey.

In all three lower layers of the atmosphere, one can see gravity waves. These are symmetrical, patterned lines that exist in the clouds in the troposphere and stratosphere and have been linked to increased risk of tornados development by a NASA project called GRITs - GRavity Wave Interactions with Tornados. In the mesosphere, these waves appear as a large bulls-eye shaped pattern visible in faint aurora, or in airglow.

In the magnetosphere, we see weakening. In fact, if the earth does not receive enough flare radiation, the magnetosphere simply weakens and more and more outer cosmic radiation comes in through the poles. When we are hit with an energetic flare, the particles become heated and excited, and the magnetosphere -- and all lower-atmospheric layers, can breath a sigh of relief. Weather is often chaotic during periods of low flaring as atmospheric collapse causes an increase in the strength and number of pressure convergences.

Here is an example of solar effects on weather: today is September 5th, 2014. The earth, a dipole magnet, is returning to a neutral axis position - not a tilted position as winter or summer. This means that we are going to be more affected by solar activity. We have not only seen strong convergence in the Midwest for days following a transequatorial coronal hole of moderate power, but we also saw a raise in seismicity - the solar pole experienced instability and we observed volcanic activity in Iceland, then Papua, and Iceland again as the charged particles streaming from the sun waned back to positive charge. There were an extreme increase of gravity waves and several instances of undulatus clouds in Iowa, mesospheric gravity waves photographed in a South Dakota, and stormy weather everywhere in the Midwest.

Expect to see activity on the sun rise for the new month or so, and then begin cycle 24's final descent towards minimum, where surprisingly some of the strongest flares occur.

My hypothesis on why we may not see much flaring is an increase in coronal hole size and occurrence, which could be due to so many outside influences it's hard to even fathom. When coronal holes are on the sun, there is less hot gas to enter the vortex of active regions and therefore less to be ejected,

This is one of the best

This is one of the best articles we have read on solar activity and long-range weather. Very complete and 100% accurate. Indeed, the developments of 2011 are confirmation of fading spots according to L&P theory, so the American Astronomical Society apparently thinks it may be worse than Dalton, calling it a possible second Maunder Minimum! Solar cycle 25 and beyond could be greatly delayed or not happen at all! "If we are right, this could be the last solar maximum we'll see for a few decades," Hill said. "That would affect everything from space exploration to Earth's climate."

As we wait for the 3rd brutal winter in a row the question is "How much worse will they get?" Sound the alarm to all the world: LITTLE ICE AGE is coming. In another stunning development, the sun had no sunspots yesterday! The whole world should stand in awe. I assure you that here at Mor Electric Heating we are VERY closely following how bad the winters will get.

I agree and wonder if this

I agree and wonder if this spring,the coldest I can remember,is related to this.I'm not a fan of cold weather and hope not but it's looking like it will be colder the rest of my life.