2012 Hottest Year On Record For Lower
48 States, NOAA Confirms
From Climate Central's Andrew Freedman:
Created with Raphaël 2.1.0
2012: Warmest Year in U.S.
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NOAA announced on Tuesday that 2012 was officially the warmest year on record in
the contiguous 48 states, based on 118 years of temperature records dating back to
1895. While not every state set a record, more than one-third (19 states) recorded
their warmest years, and three-quarters of the lower 48 states recorded their first-,
second-, or third-hottest years on record. Ninety-five percent -- 46 states -- had one
of their top 10 warmest years ever recorded, and even in the coolest state,
Washington, 2012 was warmer than 72 percent of the years on record.
Click on a state to view graph of annual average temperatures.
Source: NOAA/NCDC U.S. Climate at a Glance
Created with Raphaël 2.1.0
It’s official: 2012 was the warmest year on record in the lower 48 states, as the country
experienced blistering spring and summer heat, tinderbox fire weather conditions amid a
widespread drought, and one of the worst storms to ever strike the Mid-Atlantic and
Northeast.
According to the National Oceanic and Atmospheric Administration (NOAA), 2012 had an
average temperature of 55.3°F, which eclipsed 1998, the previous record holder, by 1°F.
That was just off Climate Central’s calculation in mid-December, which projected an
expected value of 55.34°F, based on historical data.
The 1°F difference from 1998 is an unusually large margin, considering that annual
temperature records are typically broken by just tenths of a degree Fahrenheit. In fact, the
entire range between the coldest year on record, which occurred in 1917, and the previous
record warm year of 1998 was just 4.2°F.
The year consisted of the fourth-warmest winter, the warmest spring, second-warmest
summer, and a warmer-than-average fall. With an average temperature that was 3.6°F
above average, July became the hottest month ever recorded in the contiguous U.S. The
average springtime temperature in the lower 48 was so far above the 1901-2000 average —
5.2°F, to be exact — that the country set a record for the largest temperature departure for
any season on record.
"Climate change has had a role in this [record],” said Jake Crouch, a climate scientist at
NOAA's National Climatic Data Center in Asheville, N.C. He said it isn't clear yet exactly
how much of the temperature record was due to climate change compared to natural
variability, but that it's unlikely such a record would have occurred without the long-term
warming trend caused in large part by emissions of greenhouse gases.
During the summer, nearly 100 million people experienced 10 or more days with
temperatures greater than 100°F, which is about one-third of the nation’s population,
NOAA reported.
With 34,008 daily high temperature records set or tied the year compared to just 6,664
daily record lows — a ratio of about five high temperature records for every one low
temperature record — 2012 was no ordinary weather year in the U.S. It wasn’t just the high
temperatures that set records, though. Overnight low temperatures were also extremely
warm, and in a few cases the overnight low was so warm that it set a high temperature
record, a rare feat.
Even more astonishing is the imbalance between all-time records. According to data from
NOAA's National Climatic Data Center, there were 356 all-time high temperature records
set or tied in 2012, compared to four all-time low temperature records. All of the all-time
record lows occurred in Hawaii.
As the climate has warmed during the past several decades, there has been a growing
imbalance between record daily high temperatures in the contiguous U.S. and record daily
lows. A study published in 2009 found that rather than a 1-to-1 ratio, as would be expected
if the climate were not warming, the ratio has been closer to 2-to-1 in favor of warm
temperature records during the past decade (2000-2009). This finding cannot be explained
by natural climate variability alone, the study found, and is instead consistent with global
warming.
Driven largely by the warm temperatures and the massive drought, one measure of extreme
weather conditions, known as the Climate Extremes Index, shows that it was the secondmost extreme year on record, second only to 1998. Studies show that in response to global
warming, some extreme events, such as heat waves, are already becoming more likely to
occur and more intense.
Nineteen states had their warmest year on record in 2012, mainly in the Plains and
Midwest, where summer heat and drought was the most intense. An additional 26 states
had one of their top 10 warmest years on record. Remarkably, every state in the lower 48
experienced an above-average annual temperature.
The extreme heat is even more vivid when examined at the local level. Cities such as New
York, Boston, Washington, Milwaukee, St. Louis, Denver, Des Moines, and Chicago all set
records for their warmest year.
Marquette, Mich., which is well-known for its cold and snowy winters, not only set a record
for the warmest year, but also set a record for the most amount of days above freezing
(32°F) in a single year, with 293 such days, and the number of consecutive days above
freezing, with 237.
In Des Moines, which set a record for its warmest year smashing the old 1931 record by
1.5°F, it was the first year not to reach 0°F. In addition, March had the largest monthly
temperature departure from average of any month on record there, coming in at 16.4°F
above average.
The year was also characterized by extreme drought, and two states — Nebraska and
Wyoming — also had their driest year on record. Eight more states had annual precipitation
totals that ranked in the bottom 10.
At its maximum extent in July, drought conditions encompassed 61 percent of the nation,
with the most intense conditions in the Great Plains, West, and Midwest. The nationally
averaged annual precipitation total was 2.57 inches below average, making 2012 the 15thdriest year, and the driest year since 1988, which also featured a major drought.
The drought of 2011-12, which is still ongoing, is comparable in size to severe droughts that
occurred in the 1950s, and is already being blamed for more than $35 billion in crop losses
alone, according to the reinsurance company Aon Benfield. In fact, it’s quite possible that
damage from the drought will eclipse the total bill from Hurricane Sandy, which some
estimates place at more than $100 billion. Overall, the drought could end up robbing the
limping U.S. economy’s GDP of a full percentage point, said Deutsche Bank Securities.
The drought was instigated in large part of very low snow cover and warm temperatures
during the winter of 2011, and record warmth during the spring, which allowed for an early
start to the growing season and depleted soil moisture earlier than normal. The record
March heat wave put the drought into overdrive, accelerating its development across the
Plains and Midwest in particular.
The drought conditions created ideal conditions for wildfires, as 9.2 million acres went up
in smoke in the West, the third-highest on record.
The same weather patterns that led to the drought helped suppress severe thunderstorms
and tornadoes, with a final tornado count that is likely to be under 1,000, which would be
the fewest twisters since 2002.
According to NOAA, the year saw 11 natural disasters that cost at least $1 billion in losses,
including Hurricane Sandy, which struck the Mid-Atlantic and Northeast on October 29-30.
Globally, 2012 is expected to be ranked as the eighth-warmest year on record, with that
announcement coming later in the month.