Sun's energy is very important to the Earth and it warms our planet, heating the surface, the ocean, and the atmosphere. Due to this energy, the atmosphere in our Earth drives the different weather
conditions. Our climate is also strongly affected by the Solar radiations emitted by Sun and these changes are totally based on the Earth's albedo, that is how much amount of radiation is reflected back from our Earth's surface and clouds.
The amount of radiation emitted by Sun will change with solar activity like Solar flares or sunspots. Solar activity is known to vary in cycles, like the 11-yr sunspot cycle(Sometimes even longer than expected). Few scientists are wondered with if the changes in the Earth's climate and weather might be linked with the short or long term solar cycles. Weather is the current atmospheric conditions, including temperature, rainfall, the wind, and humidity for selected area. On other hand, the climate is the general weather conditions over a long time. This is one of the most active areas of research for decades and also an example of scientific process.
Some scientists tried to find an actual link between changes in Earth's weather and solar variability. Although few scientists reported such correlations, but the studies didn't find the exact same results, casting the doubts or disproving the original studies. Examples that includes the studies of the link between the number of sunspots and changes in the wind patterns, or between cosmic rays and clouds.
Many studies looked at the effect of solar variation on Earth's climate, again with mixed success. Whenever a change occurs in the sunspots cycle then there will be an automatic change in the amount of solar radiation emitted by Sun, but only changes by a little bit. These changes aren't enough to account for the majority of the warming observed in Earth's atmosphere over the last half of the 20th Century.
The other thing that made the Earth's atmosphere feel warmer is the addition of greenhouse gasses. If you would like to know more about the relationship between solar variation and climate
visit: Intergovernmental Panel on Climate Change’s Frequently Asked Questions section of their recent report.