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Book It: 2012, The Hottest U.S. Year on Record

Research Report by Climate Central

Average annual temperature in contiguous U.S.
Click image to enlarge.

Report Summary

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Global warming is directly linked to only a few weather events and climate trends. One of them, however, is warming itself, which could make 2012 a watershed climate change year in the U.S. More than superstorms, wildfires, and devastating drought, this year’s record-smashing spring and summer heat waves, with their melted airport runways and warped steel rail lines, are more evidence that climate change is real.

Last week NOAA announced that 2012 was “likely” to be the warmest year on record in the 48 states, based on temperatures through November. At some point, however, likelihood turns into certainty. Does a warm December push the nation to the point where it is impossible for 2012 to be anything but the warmest year ever recorded in the U.S.?

To answer that question Climate Central did the math, and the results are in.

  • There is a 99.99999999 percent chance that 2012 will be the hottest year ever recorded in the continental 48 states, based on our analysis of 118 years of temperature records through Dec. 10, 2012.

The five warmest years since 1895 and then 2012 through November.
Click image to enlarge.
Click here for a zoomed in view of Aug.-Dec.

By taking the top spot as the hottest year in the U.S., 2012 pushes 1998 into second place, followed by 2006, 1934 and 1999. In line with the global warming trend spurred by steadily rising carbon emissions, seven of the top 10 warmest years in the 48 states have occurred in the past 15 years.

Like so much recent record-breaking weather, 2012 isn’t just going to break the previous record, 2012 is looking to smash it, by more than 1°F. Climate Central projects the 2012 average temperature for the continental U.S. at 55.34°F compared to the previous record set in 1998 of 54.32°F. For perspective, 1°F is one quarter of the difference between the coldest and warmest years ever recorded in the continental U.S. 

Exactly how cold would it need to be not to break the record? Temperatures would have to average 14.76°F across the continent for the rest of December — a holiday season colder than any ever recorded.

But that is not going to happen. So far this December the mean temperature in the contiguous U.S. has been 44.13°F. The average temperature for 117 years of previous Decembers is 33.08°F.

Distribution of Dec. 11-31 average temperatures, 1895-2011.
Click image to enlarge.

Things are a bit different at the state level, where the heat was extreme, but far from every state will set the record. Fully two-thirds of the lower 48 states recorded their first-, second- or third-hottest years through November, and 43 states had one of their top 10 warmest years ever recorded. Even the coolest state, Washington, had a far warmer-than average year to date.

But while 17 states had recorded their warmest year to date, just 12 have better than a 50-50 chance of continuing this warm weather through the year and having the warmest year on record. (State odds will change as we move toward the end of the year.) 

Record-shattering heat has been the norm all year. June-through-August 2012 was just two-tenths of a degree cooler than the Dust Bowl summer of 1936, and July of this year was the hottest month ever recorded in U.S. history.  

This scorching summer followed on the heels of a remarkably warm spring in most of the country. March 2012 was the warmest March in U.S. history by a wide margin. In communities across the upper Midwest, daily low temperatures routinely broke previous high temperature records, and daily high records were repeatedly smashed by 20 degrees or more.


By Peter Guttorp (98115)
on December 13th, 2012

You are not taking into account the uncertainty in the temperature estimates. This uncertainty also makes the rankings uncertain. See

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By Daniel Scheinhaus (Valley Stream, NY 11580)
on December 14th, 2012

I’m on a Nation Magazine cruise where we’ve had talks on various topics about a variety of political problems we’re having. Unfortunately, while climate change should simply be a scientific awakening and dispersion of the facts among the populace, it’s also a political problem. It has been made so because there are powerful industries that would be hurt financially if the world took strong measures to arrest the changes taking place. As a result, governments have to take steps to help these industries (is bribe a better word?) to switch their businesses to other sources of energy in ways that cushion the losses for them. In the meanwhile, we have to watch in helpless panic while nothing significant is being done.

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By Robert Harmon (St. Augustine, FL)
on December 14th, 2012

And Peter, your point is? Climate Central, thank you for this important report, and for your objectivity. I see you post comments from the literate and the illiterate.

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By Tokodave (Butte, Montana 59701)
on December 14th, 2012

They don’t look that uncertain to me??

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By Ronnie (Minneapolis, MN. 55406)
on October 13th, 2014

“There is a 99.99999999 percent chance that 2012 will be the hottest year ever recorded in the continental 48 states,...”

It would seem that a calculation to within ‘One Millionth of 1%’ is a bit more than certain. It is down right absolute.

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By Bill (Long Beach, NY)
on December 14th, 2012

Average Global Temperatures have remained flat or have showed a slight cooling trend since 1997 - this is a fact. Hard science has proven that Carbon is a weak greenhouse gas in concentrations that are similar to the concentrations in our atmosphere. NASA has shown that most current climate models drastically underestimate the amount of heat that simply radiates out of our atmosphere. Polar bear populations have never been healthier. Where are the facts that point towards your literacy? You make fun of someone because one article says the US had high temperatures.

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By Barry Carter (Baker City, OR 97814)
on December 14th, 2012

The best solution may be to pull more carbon from the air into the soil and plants using a method described at:

The best thing about this solution is that it does not require corporate or government cooperation. Everyone can do it on their yard, garden or farm.

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By Jan (los angeles/CA/90041)
on December 15th, 2012

Ocean temps are don’t fluctuate as much’ and show a persistent,  gradual average increase through the last few decades.  Then there is unprecedented and rapid melting of Arctic ice and glaciers not seen before,  And hot records broken far more often that cold records.  They would average out equal in a stable climate. Their ration hot/cold is increasing with each decade.  If it walks like a duck….

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By MikeH
on December 15th, 2012

Bill from Long Beach
Your claim “Hard science has proven that Carbon is a weak greenhouse gas ...” is a lie. Your claim ” NASA has shown that most current climate models drastically underestimate the amount of heat that simply radiates out of our atmosphere” is also a lie. Your claim “Polar bear populations have never been healthier” is also a lie.

You can go here to find out what NASA believes about climate change.

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By Jeff (Surrey, BC, Canada)
on December 16th, 2012


Re: the planet has been cooling since the late 90’s:

Re: CO2 has little to no effect:

Re: Polar bears are not in trouble:

You’ll find links to sources that prove you’re wrong. Not surprising that you provided no sources of your own for your statements that go so staunchly against the scientific consensus. Extraordinary claims require extraordinary proof…..and when you represent the view of a few kooks, your claims definitely count as extraordinary.

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By Leslie Graham
on December 17th, 2012

The same old thousand-times-falsified myths and lies from the same old er…skepticks” over and over and over again.
Give it up guys. You’ve been busted. Change the record. No-one but the most deluded and gullible agendised whackjobs are still falling for that wearisome junk.

Some of the claims above are so obviously absurd as to be not even worth debunking yet again but I’ll just pick one at random to do my bit for scientific fact.

For example, this lie is commonly parroted all over the web:

“Polar bear populations have never been healthier” 

When the truth - which anyone could find for themselves in about two minutes - is as follows:

The Polar Bear Specialist Group is composed of researchers and managers representing each of the five circumpolar nations that signed the International Agreement for the Conservation of Polar Bears of 1973. At their last international conferance in 2009 they concluded:

“..Reviewing the latest information available the Polar Bear Specialist Group (PBSG) (an international concluded that 1 of 19 subpopulations is currently increasing, 3 are stable and 8 are declining.  For the remaining 7 subpopulations available data were insufficient to provide an assessment of current trend…”

I don’t know about anyone else but I prefer to get my facts about polar bears from organisations such as the PBSG rather than from anonamous climate trolls who simply parrot the nonsense that does the rounds on the denierblogs like WattsUpWithThat.

“If the deniers are so sure of their case why do they lie all the time”

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By Robert (California)
on December 17th, 2012

Why are we looking at U.S. data when discussing global warming? Shouldn’t we be looking at global temperate data instead of just one spot on the globe?

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By Zivnuska (Wichita, KS 67220)
on December 18th, 2012

We’re being Koch’d.

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By Justus
on December 21st, 2012

First of all, this article is about temperatures in the United States.  2012 is NOT the warmest on record, and it would take one hell of a December to make it the record.  The fact that, since temperatures continue not to rise with insane predictions by the IPCC shows that some people who predicted 130 degree temperatures in Phoenix need to re-adjust their predictions (yet again). 

Also,  there were only a handful of plar bears in the 1970s recorded.  We now see tens of thousands.  Whether or not the polar bear populations have been declining recently is meaningless, and considering we see no such decline since the 70s, it is not a correlation with Global Warming. 

Also, please use peer reviewed sources when composing your argument.  Skepticalscience is a blog, and NASA’s statements are not peer reviewed prior to release.  We need to only use statements that are subject to tough editorial guidelines considering I could pull statements from skeptics just as easily (yes, there is an “outside the bubble” liberals, not everyone agrees with you).

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By A. Scott (MN)
on December 23rd, 2012

First “.... on record” is a convenient untruth.  Certainly there was climate before the last “118 years.” And there is a significant record of climate data prior to then as well.

AGW proponents completely ignore the historical climate record - which operates in well known appx 125,000 year glacial cold to inter-glacial warm climate cycles.

We have OBSERVED temp records going back 400 years. We have written anecdotal evidence going back far further than that - observing climate related issues such as growing regions and iced over rivers and the like.

SECOND - we have a relatively good temperature and CO2 record of the last 15,000 years from Vostok and Dome C ice cores, corroborated by a number of other various proxies. We know beyond a reasonable doubt that the temperatures began climbing - out of a glacial cold minimum - a bit less than 15,000 years ago. We also know that the global temps climbed sharpley, as is customary in an inter-glacial period, until appx 11,000 years ago. For the last 11,000 or so years temps have remained remarkably stable, trending up and down within a several degree C range. The recent increases - over the last appx 100 years - are wll within the natural variability of the last 10,000+ years of STABLE temperatures.

There is nothing unique, unusual nor unprecedented about the last 100 years temps, when compared to the last 10 years record. Only by IGNORING the last 10,000 years and comparing recent increases with a baseline of 1961-1980 can warming proponents draw their conclusions.

The 15,000 year temp record (from appx 2000 - current temps are almost identical to the peak during the Medieval Warm Period, which si well within the natural variability of the last 10,000+ years. It should be noted the CO2 levels during the last 10,000 years have continued to climb, yet the long term temp trend is extremely stable, within a small variable range.

Like wise the last 16 years of no cooling, have also occurred despite the continued rise of CO2. The second link shows the last 16 years - WFT uses the direct data from the original sources. Anyone can plot their own graphs from the data sets. This shows HADCRUT Land temps, HADSST Seas Surface Temps and RSS Satelitte lower troposphere air temps - along with the trend line for each. You can see CO2 has continued to increase while each of the temp components trends remain flat.

And the Met Center in UK, despite their attempts to defect teh discussion, admit the same.  .

15,000 year Temp Record:

WoodForTrees 1997-2012 Global Air, Land and Sea Temps w/CO2

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By Richard lawson (Bs25 5nt)
on December 28th, 2012

MN, if it is Ice Age cycles you are interested in, take a look here:
I was surprised to find that the next Ice Age cooling cycle will have very little effect on the warming from increased GHGs.

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By Hank Roberts
on January 6th, 2013

The obfuscated link to Woodfortrees above hides the site’s information that using the Woodfortrees trend lines
allows intentional misrepresentation of the trend.

Look at the site’s Notes page for the rest of that: where he writes:

“... After many requests, I finally added trend-lines ...  by picking your start and end times carefully, you can
now ‘prove’ that:....    Temperature is static! ...”

There ya go.

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By Hank Roberts
on January 6th, 2013

PS:  I do agree with another commenter above that showing just the contiguous 48 states isn’t really useful science.  That smacks of, you know, journalism.  The article should at least compare the overall global number and cherrypick another contiguous continental area that has a different result—rather than leaving that for the climate deniers to do. 

When you write this:

” Climate Central did the math, and the results are in.
  There is a 99.99999999 percent chance that 2012 will be the hottest year ever recorded in the continental 48 states, based on our analysis of 118 years of temperature records through Dec. 10, 2012.”

You should show your work.  Statisticians, and those who appreciate what statisticians do, would likely be quite interested in the way you got these numbers.

Again, this reads like journalism.  But you have scientists on the staff.  Show _their_ work.

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By Cal
on January 7th, 2013

“Average Global Temperatures have remained flat or have showed a slight cooling trend since 1997 - this is a fact.”

No, Bill, that is not a fact. It is a lie.

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By Rob (GA, USA)
on January 15th, 2013

Hank, highlighting the disclaimer in the WoodForTrees site does in no way make your case of the trend lines it generates using various global mean temperature data-sets (the same used by the IPCC).  Are you somehow indicating that the underlying data has been modified or that the statistical trend calculations are incorrect?  Please clarify and be specific.

Also, stating that the overall trend from 1998 (El Nino) to the present is based on a cherry-picked range to show no statistically significant warming is ludicrous.  Think of it this way, start from today and work your way backwards until the trend clearly shows statistically significant warming (prior to 1998).  It is a simple fact that anyone can see in a few minutes (and you don’t even need to use WoodForTrees).  I don’t see how anyone can disagree with this when all of the key data-sets are publicly available.  Prove me wrong on this and, no, the answer is not that this decade is one of the warmest’s on record (think about what the really means).

As others have already mentioned, there is no point or purpose in highlighting US only temperature records when the overall context is Global Warming.

By the way, it is refreshing when dissenting or skeptical comments are not summarily deleted as is common with several other pro-AGW sites.  ++Rob

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By Rob (GA, USA)
on January 15th, 2013

Cal, care to prove that it is a lie based on the actual data you can access easily?  Please don’t bother posting a like to the Skeptical Science blog.  If you bother to actually analyze the data, you will see the truth.  ++Rob

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By Robert B (mission viejo, ca 92692)
on February 8th, 2013

I thought the issue was global warming, not U.S. warming.  2012 wasn’t even close to the warmest year globally.

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By greg (Sag Harbor, NY, 11963)
on August 2nd, 2013

We know that emissions in the US have dropped over the past 30 years.  This is a fact.  Yet you are trying to state that anthropomorphic warming has caused the heat we felt last year.  From my personal experience, living in the lower 48, I also totally disagree with your broad statement.  My experience in the NY area is that 2012, at times, was warmer than usual, but at times, it was colder.  In all, it was a colder year than in the decade prior.  As others have said, cherry picking places and regions, or individual data collectors, in order to prove some statement is a losing proposition, and reeks of fraud, or at best, misleading others.  in this very political cause-related site, it also stinks of political motivation, attempting to affect public discourse, leading to public policy that will destroy our economy.

The link to statmos up on top of the comments seems very poignant.  The work you point to is NOT peer reviewed, and therefore is less credible than other work, which vary greatly from survey / conclusion to another, from denier to believer.  Unfortunately, we also know that the worldwide organizations that have collected and dissected the data (NASA, NOAA, IPCC, etc.) have their own agendas, and have fudged both the raw data (by progressively eliminating colder regions, and using naturally warming individual data retrieval points), and have reversed their beliefs in order to maximize the political effect and increase their prominence. 

The fact that we are in an interglacial warming period is a given.  This should tell the story right there.  During every interglacial warming period we can track, temperatures got progressively warmer, and CO2 vacillated during those times, with times in the middle that didn’t comply with the long-term trends, and micro-climates across the globe that defied the temperature changes around the globe.  Hence Greenland’s name.

It’s impossible to imagine a situation where the earth can possibly heat up, as a whole, 2 degrees C over the next 27 years, considering the lack of momentum in overall earth temperatures over the past 10-15 years.

And finally, it’s impossible to correlate any expenditure in “global warming efforts” or carbon tax in general to a potential change in the course of worldwide temperature change over the next century.  That is just a get-rich-quick scheme on the part of the governments involved, and of certain unscrupulous (bordering on criminal) individuals who get hundreds of millions of dollars to go to Finland to build extremely inefficient cars for fat cats.

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