Sunspots and Weather

The possible connection between sunspots and weather gets talked about so much these days that it is easy to make the mistake of believing there is a proven relationship.

The primary energy source that drives the earth's weather is sunlight. As far as is known, the output of light from the sun is constant; it is not thought to vary with the 11-year sunspot cycle.

However there is another form of energy carried from the sun to the earth, and it does vary with sunspot activity. This is the energy carried by moving particles, mostly electrons and protons, in what is called the solar wind.

The solar wind flows outward from the sun just as sunlight does, but at a much slower pace. It takes sunlight about eight minutes to reach the earth whereas particles in the solar wind take a day or two.

Sunspots come into play because from or near them emerge streams of particles which enhance the solar wind, sometimes rather drastically. When these enhanced solar wind flows strike the earth, we see more aurora and there are other related effects. The aurora and the related effects clearly demonstrate that the earth is receiving energy other than light from the sun.

But does this additional energy affect the weather? One reason it might not is that it is such a tiny amount of energy compared to that received in the form of sunlight, only about one-hundred-millionth as such. So if this comparatively small energy does have an effect on weather, it probably acts as a trigger to some more energetic process.