It is believed that sunspots play a roll in temperature here on earth. Basically, the theory is the more sunspots the warmer it gets on earth. This commentary on the relationship is from the National Weather Service:
From the mid 1600s to early 1700s, a period of very low sunspot activity (known as the Maunder Minimum) coincided with a number of long winters and severe cold temperatures in Western Europe, called the Little Ice Age. It is not known whether the two phenomena are linked or if it was just coincidence. The reason it is hard to relate maximum and minimum solar activity (sunspots) to the Earth's climate, is due to the complexity of the Earth's climate itself. For example, how does one sort out whether a long-term weather change was caused by sunspots, or maybe a coinciding El Nino or La Nina? Increased volcanic eruptions can also affect the Earth's climate by cooling the planet. And what about the burning of fossil fuels and clear cutting rain forests? One thing is more certain, sunspot cycles have been correlated in the width of tree ring growth. More study will be conducted in the future on relating sunspot activity and our Earth's climate.The photograph of the sun taken above is from a link that updates with the latest photograph of the sun. As you can see, there are no sunspots. And there have been almost zero over the last couple of weeks. The last solar cycle has mostly ended and typically a new one would have begun. But it hasn't happened. The end of the last solar cycle and the current absence of sunspots coincides with the largest drop in temperature over a 12 month period in recored history. This is a record drop in temperature correlating with a record absence of sunspots. In my opinion the correlation between low sunspots and a drop in temperatures, both now and during the Maunder Minimum or "little ice age", bolsters the argument for causation.
The Solar Cycle: Sunspots increase and decrease through an average cycle of 11 years. Dating back to 1749, we have experienced 22 full solar cycles where the number of sunspots have gone from a minimum, to a maximum and back to the next minimum, through approximate 11 year cycles. We are now well into the 23rd cycle, with the 24th cycle right around the corner. The number of sunspots in this cycle reached a peak in May, 2000 where the number of sunspots were measured at near 170. A secondary sunspot maximum occurred near the beginning of 2002 where the sunspot number was about 150. The next sunspot minimum is forecast to occur in late 2006 through mid 2007.