Crazy Hot December: USA Edition

This December was crazy hot. And not just in England; it was in the eastern U.S. too.

The National Center for Environmental Information has released the December figures, and they’re staggering. Of the 48 states in the conterminous U.S., only 10 had near-average temperature, 3 were above average, 6 were much above average. A whopping 29 out of 48 were the hottest on record.


Many states didn’t just break the record by a little, but by a country mile. Take New Jersey, for instance. This December averaged 6.2 deg.F hotter than any previous. That’s fully 1.48 standard deviations above 2nd place. Not 1.48 standard deviations above average — it’s 1.48 standard deviations above 2nd place.


Consider Delaware. It was 6.1 deg.F hotter than 2nd place. That’s 1.45 standard deviations above 2nd place.


Some states didn’t just break the record for hottest December, they broke the record for hottest temperature anomaly of any month. States like Rhode Island:


And that’s not the only one. Fully 16 out of 48 states broke the record for hottest temperature anomaly of any month.

Of course these record-shattering temperatures are the combination of trend and fluctuation. The fluctuations were hot, and we can expect such fluctuations to happen again. After all, fluctuations gonna fluctuate — they just won’t stop.

But the trend is also toward hotter and hotter temperatures. When the two conspire, you break records. That’s what happened.

It’s bound to happen that fluctuations will go in the other direction. That’s the nature of fluctuations — sometimes up, sometimes down, sometimes a little, sometimes a lot. When temperatures fluctuate downward, expect deniers to bray about how cold it is — how there was ice in winter — how they found a snowball! They’ll keep braying until the fluctuations go back up. Then they’ll whine about how a single record month “don’t mean a thing.”

As for the trend … expect that to keep going up.

If you like what you see, feel free to donate at Peaseblossom’s Closet.

27 responses to “Crazy Hot December: USA Edition

  1. XKCD had this pegged a while back:

  2. The Peaseblossom’s Closet link goes to a PayPal error: “Sorry — your last action could not be completed”

    [Response: Thanks. I think I fixed it, but considering all the problems I’ve had with PayPal, I can’t be sure. You can try again if you like.]

  3. Where I live, Greensboro, NC area, the December average temperature was 53.4°F, which was 13.2°F above the 1951-80 average. This was the warmest December that this area has seen since records began. If others are interested in this data, it can be found over at the Climate at a Glance page from NOAA:

  4. skeptictmac57

    “All About That Trend”

    Because you know it’s all about that trend
    ‘Bout that trend no yo-yo
    it’s all about that trend
    ‘Bout that trend no yo-yo
    it’s all about that trend
    ‘Bout that trend no yo-yo
    it’s all about that trend
    ‘Bout that trend…trend…trend…trend

    Try getting that out of your head ;)

  5. That we have one more warmest december/january/quarter/year/whatsoever seems to be not so interesting, as it is to be expected every now and then with the trend given. That we got a real outlier from the trend is somewhat more interesting indeed, and especially interesting would be how much more probable such events become. Is there, in addition to the trend, a higher variability on the regional scale to be observed, and can it be quantified?
    Also interesting are the repercussions of those outliers, as they bring the system in states of much higher feedbacks kicking in, both positive and negative. I think of snow cover, water vapor, vegetation, methane release and the like. One possible outcome beeing, that the higher variability yields an extra acceleration of the process, with respect to what would be expected just from the trend.

  6. I am planning to do a simllar analyse for the Quebec. This year was probably the hottest december ever and last year the coldest winter ever. The term in that case, mean at least down to 1840, but more likely since the fondation of the colony in 1608.

  7. Bbbbbut Tom Harris of the “International Climate Science Coalition” just posted a comment (which he clains is based on NOAA state records) stating, “Clearly, on a state-wide basis, there is no increase in extreme weather records.”

  8. Yeah, that is pretty much what I’e been telling folks, except more sophisticated! Thanks, I’ll share this!

  9. UAH ranks December 2015 as only the fourth warmest – behind 1980, 1979 and 1994. Complete rubbish, courtesy of Drs. Spencer and Christy. Those years aren’t even close on the surface records, and it certainly wasn’t because higher elevations of the LT were colder. On the contrary, we were shattering upper atmospheric temperature records on numerous occasions during the month. Somebody needs to call them out for publishing nonsense. It’s clear there is a spurious cooling trend, and v.6 only aggravated it.

  10. Dave – it may well be that there’s a problem with the satellite datasets, but let’s not fixate on UAH. They’re in near complete agreement now with RSS and I don’t believe there’s any reason to doubt RSS is doing their best to be accurate.

    As has happened before, there’s something going on we don’t yet understand; sensor drift, calibration drift, formula errors – who knows? But it’s not a problem we can lay at the feet of Spencer & Christy; RSS shows the same results.

    • How much the same are RSS and UAH really? Are we talking global? In that case it is weird they are the same, since RSS excludes a much larger portion of the world (at the poles).

  11. Hi, new here..

    But I bin doing some calcs you might want to check

    My calcs show that UAH as USA48 and USA49 both as the WARMEST year in the USA in the satelite data. RSS has USA in 2nd place.

    Someone might want to check this and use it.

  12. UAH in order to get their product to match with RSS had to significantly change the altitude profile, including more stratospheric data.

  13. In order to match RSS UAH had to change the altitude profile to include more stratospheric data.

  14. It looks like UAH ranks it as the third warmest (see

    I believe that there also tends to be a lag with El Nino between the surface warming and the LT warming. Even Spencer admits that it is likely that next year will set a new record. (“Since 2016 should be warmer than 2015 with the current El Nino, there is a good chance 2016 will end up as a record warm year…it all depends upon how quickly El Nino wanes later in the year.”)

  15. Tried to post here twice but they both vanished! UAH changed their altitude profile to match RSS, peaks at 4km as opposed to 2km previously. Includes more stratosphere.