Last year was the warmest year on record in the contiguous 48 states, according to a report released Tuesday by the federal agency that tracks climate. According to the National Oceanic and Atmospheric Administration, the average temperature in 2012 was 55.3 degrees Fahrenheit — 3.2 degrees above normal and one degree higher than 1998, the warmest year previously on record. Last year was also a historic one for extreme weather, the NOAA study found, with 11 natural disasters that cost more than $1 billion, making 2012 second only to 1998 in the agency's extreme weather index. The record heat in 2012 was felt nationwide, by farmers whose crops were decimated by the heat and drought as well as by Chicagoans bracing to break a 72-year snowless record. If the city doesn't see snow before Wednesday, it will mark the longest stretch — 319 days — without an inch on the ground since 1939 to 1940, NBC 5 Chicago reported.