In my position as Tech/Customer Support here at TC Life Safety, I get this question a lot. And since we are dealing with Life Safety, I don't want to just give you my opinion without backing it up with the science of the issue.
How crazy has the weather been? I am writing this and Anchorage Alaska is warmer than my home in Massachusetts... Call it the effects of global Warming or Environmental Change, it is all a part of the Greenhouse Effect blamed on aerosols.