The seeming relationship between sunspots and climate has been known about for around 200 years. I've just finished reading a book called "The Sun Kings" by Stuart Clark and learnt it was William Herschel who first noticed the relationship between sunspot numbers and the wheat prices.
For those not aware of it, a lack of sunspots correlates with cooler global climate and higher sunspot numbers with higher temps. It has been easy enough to trace the past history of sunspot numbers past recorded history with dendrochronology and the C13/C14 ratio in tree rings and for solar flare activity the amount of nitrates in snow in polar regions indicates strong auroral events caused by flares.
This topic is currently verging on being controversial. While on one hand there does seem a very clear relationship between sunspots and climate, no one has a good explanation of why. And this is only for long term climate, as in seasons, not daily weather. The last attempt to explain how cosmic rays encourage cloud formation was rubbished by the proposers scientific peers (times of low sunspot numbers lead to a quieter magnetic field around the earth and that allow more cosmic rays down to the ground).
For some calm, positive and pro-sunspot influence on weather discussion I would direct you
here for starters. I find it a very interesting topic but I'm wary of jumping on any particular bandwagon until the hard proof is in the bag.