So far this year, the U.S. is running a distinct fever, as the lower 48 states had its warmest January-to-May period on record, according to the National Oceanic and Atmospheric Administration (NOAA). Other longstanding records have fallen as well, including the record for warmest spring, which dated back to 1910 and was smashed by 2 degrees Fahrenheit.

Taking a deeper dive into the temperature statistics reveals fascinating insights into just how warm it's been at the local level in many locations. As NOAA stated on its website on Thursday, "In some locations, 2012 temperatures have been so dramatically different that they establish a new "neighborhood apart from the historical year-to-date temperatures."

The year-to-date numbers were certainly boosted by the unprecedented heat wave that took place during March, when several thousand warm temperature records were shattered from the Rocky Mountain states on eastward. Global warming raises the odds of heat extremes, and natural variability has favored warmer-than-average conditions so far this year as well. This has had a profound effect at the local level this year.

Take Chicago, for example. With a January-to-May average temperature that was 7.1°F above average, or 3.1 standard deviations above the 1981-2000 norm, this year so far stands in a class of its own — the warmest in 54 years of recordkeeping.