The numbers are in: 2012, the year of a blistering March heat wave, a severe drought in the Corn Belt and a massive storm that caused broad devastation in mid-Atlantic states, turns out to have been the hottest year ever recorded in the contiguous United States.
How hot was it? The temperature differences between years are usually measured in fractions of a degree but last year blew away the previous record, set in 1998, by a full degree Fahrenheit.
If that does not sound so impressive, consider that 34,008 daily high records were set at weather stations across the country, compared with only 6,664 record lows, according to a count maintained by Weather Channel meteorologist Guy Walton, using federal temperature records.
That ratio, which was roughly in balance as recently as the 1970s, has been out of whack for decades as the country has warmed, but never by as much as it was last year.
The heat was remarkable, said Jake Crouch, a scientist with the National Climatic Data Center in Asheville, N.C., which released the official climate compilation Tuesday. It was prolonged. That we beat the record by one degree is quite a big deal.
Wichita and Chanute both recorded their warmest years on record in 2012, according to the local branch of the National Weather Service. Wichitas average temperature last year was 61.4, more than four degrees above normal. The average temperature was above normal every month of the year in Wichita.
Scientists said that natural variability almost certainly played a role in last years extreme heat and drought. But many of them expressed doubt that such a striking record would have been set without the backdrop of global warming caused by the human release of greenhouse gases.
Even so, the nations 2012 record is not expected to translate into a global temperature record when figures are released in the coming weeks. The year featured a La Nina weather pattern, which tends to cool the global climate overall, and scientists expect it to be the worlds eighth- or ninth-warmest year on record.
Assuming that prediction holds up, it will mean that the 10 warmest years on record all fell within the past 15 years, a measure of how much the planet has warmed.
Last years U.S. weather began with an unusually warm winter, with relatively little snow across much of the country, followed by a March that was so hot that trees burst into bloom and swimming pools opened early. The soil dried out in the March heat, helping to set the stage for a drought that peaked during the warmest July on record.
The drought engulfed 61 percent of the nation, killed corn and soybean crops and caused ranchers to thin livestock herds. It was comparable to a severe drought in the 1950s, Crouch said, but not quite as severe as the Dust Bowl drought of the 1930s, which was exacerbated by poor farming practices that allowed topsoil to blow away.
In addition to being the warmest year since extensive records for the contiguous United States became available in 1895, last year turned out to be the second worst on a measure called the Climate Extremes Index, surpassed only by 1998.
Experts are still counting, but so far 11 disasters in 2012 have exceeded a threshold of $1 billion in damage, including several tornado outbreaks; Hurricane Isaac, which hit the Gulf Coast in August; and, late in the year, Hurricane Sandy, which caused damage likely to exceed $60 billion in nearly half the states, primarily in the mid-Atlantic region.
For people who escaped Hurricane Sandy relatively unscathed, the year may be remembered most for the sheer breadth and oppressiveness of the summer heat wave. By the calculations of the climatic data center, a third of the nations population experienced 10 or more days of summer temperatures exceeding 100 degrees Fahrenheit. Wichita had 36, including 21 in July.
Contributing: Stan Finger of The Eagle