Weather patterns are very chaotic in the official sense of the term. That means from week to week, month to month, and year to year, there can all kinds of weather extremes.

Even without global warming, there would be stretches of mild weather and stretches of extreme weather. It is true that global warming has the potential to aggravate this stuff, because more warming means more energy, means energy means more weather extremes.

However, the amount of variation in weather from year to year is insufficient to use as a measure of global warming at this point. Other measures of global warming indicate it is happening but other factors such as La Nina and El Nino can make one year's weather be very different than another year's weather.