A little patch of denial
Given variations of climate, there were also a few small patches that were cooler than average. Unfortunately, one of those patches covers the eastern (and more densely populated) half of the United States. Remember this map when some denialist points to conditions within just the US as evidence that global warming is not happening. They don't seem to realize that the US is only about 2% of total planetary surface area, or that it can't be kept insulated from the effects of what happens to the other 98%.