Some of the fluctuations are from the arctic jet stream in the north wobbling and the gulf trade winds from the warm caribbean sea and warm winds of off the pacific coast from the continued elninia weather patterns. The jet stream is fluctuating due to the warming of the Atlantic Ocean and the melting glaciers around the poles mixed with the solar radiation from the sun. It really is climate change, whatever the cause I'm not gonna argue that, but it is climate changing due to warming surface temperatures. We don't notice the changes in the summer time as much unless a cold front creates thunder storms and potentially tornadoes.