Shifting weather patterns could be the result of natural phenomenon, but given the state of everything going on in the world and I believe the case is closed. The weather is going to continue to spiral out of control. I believe we are living in the end times, and these natural disasters are going to culminate with a large decline in the population.
While shifting weather patterns are definitely a problem, and may in fact herald the end of life as we know it, they are not an indication of "end times" as it is intended in this question. The bible is a work of fiction, and the idea that some higher power is causing the end of the world is insane. We are creating our own downfall by spilling tons and tons of pollution into our atmosphere, warming the oceans and creating conditions to wipe out life on earth.
Despite the difficulties we have predicting the weather, weather patterns are a product of natural phenomena, not anything supernatural. It is an incredibly complex process that must take account of many intricate factors, but we do generally understand how they work. Add to that the no end of times prediction has ever been correct, and very few of them scientifically supported in any way, and the likelihood of shifting weather patterns being part of the end times is very low.
Given the fact that we have ruined our world over the past hundred years it is likely more suspect that we are the cause of it. To say it's the end of times is just to cause everyone to be upset and to freak out over nothing. We are just a blip on the radar.