World's hottest-ever recorded temperature turns 100

If you needed an excuse to perhaps grab an ice cream cone or a Popsicle, you can say you're celebrating the 100 year anniversary of the hottest temperature ever (reliably) recorded on Earth.

It was July 10, 1913 when Death Valley, California recoded a high temperature of 134 degrees -- a number yet to be matched anywhere else on the planet (at least, officially).

That hot day was among a stretch of heat where Death Valley would reach 130 two days later and then 131 on the 13th. It stands today as the only three recorded temperatures at or above 130 degrees there stretching back to 1911. (There is more to that story I'll get to in a bit.)

The celebration comes as Death Valley is probably still getting used to its status as world's hottest temperature holder. For 90 years, that distinction was given to El Aziza, Libya which had recorded a 136.4F degree reading (58C) on Sept. 13 in 1922.

But last September, on the 90th anniversary of that record, the World Meteorological Organization stripped Libya of its title after a two year investigation, citing five troubling aspects about the measurement including a potential problem with the thermometers, and a new, inexperienced observer.

The 136 degree reading didn't really match well to surrounding readings taken at the time, didn't match current weather conditions, and also didn't match subsequent observations. In other words, the reading came out of left field.

The record has always faced suspicion in the weather community over the years -- in the 90 years since that record, no Earthly temperature has even come close. But in 2010, Christopher Burt, who writes the awesome "Weather Extremes" blog for Weather Underground took it upon himself to delve into the record to see if it could be proven for good, one way or the other.

He got in contact with the director of the climate department in Libya, who was eager to help and provided much data to Burt, including the original records of the observation -- something that had not been seen before.

Burt's blog details how the investigation proceeded. Among the "smoking guns" of the investigation was a note that a new, inexperienced observer was put in charge just two days before the 58 degree temperature was recorded. Also of note on that day, the temperature readings were about 7 degrees (C) warmer than surrounding stations. Thermometers at the time used a peg that sat on top of the mercury and would remain there at the day's highest spot, recording the high temperature. Burt said the peg was roughly the height of 7 degrees on the thermometer scale so it is possible the observer erroneously read the top of the peg as the day's high instead of the bottom and it was "only" really 51C (124F) that day.

So much like the runner up in Miss America getting the title when the champion resigns, the title fell to Death Valley's 134 in 1913. But there are some suspicions about that record as well.

Death Valley's record a surprise considering nearby thermometer readings

Burt wrote another blog entry going through all of the hottest temperatures recorded around the world and presenting his evidence of their flaws and why they're not considered official. (It too is a great read. My favorite story is a record that had stood for a long time: a 54 degree C (129F) reading in Israel in 1942. But you can see on the bar chart the temperature only hit 53, but the person misread it and noted 54. The 54 had stood as hottest Asia temperature until this obvious error was discovered.)

And along those lines, Burt (and many others) have found that Death Valley's now-record 134 degree record has some suspicions as well -- mainly that surrounding stations reported temperatures below 120, and that Death Valley has yet to reach 130 again in the 100 years since.

Here is the official list of records for Death Valley since 1911:

(Note: The June 30, 2013 temp has since been updated to 129)

And here is how Death Valley shaped up with their highs (black line) versus surrounding sites. Death Valley was on average about 13 degrees warmer than these cooler sites but that week of 130s, they were at times over 20 degrees hotter.

Chart courtesy: John Christy

Burt says while there are these suspicions, there is no conclusive evidence to overturn it so it stands today and there is a big party down there to mark the 100-year anniversary.

But even if some day the WMO were to invalidate Death Valley's stretch of 130s, the record would stay at Death Valley. The spot has recorded 129 a handful of times using modern thermometer equipment (including just last month on June 30!) and some say it is probably the most accurate highest temperature recording on the planet. (Just think, they could have six parties a year celebrating 129 than just the one now!)

They just have to hope no one is brave enough to ever put a thermometer out in Iran's Lut Desert. There are no observation stations there but some infrared satellite images have suggested ground temperatures that have reached around 70 degrees C -- or 158 degrees F!

By the way -- the forecasted high temperature in Death Valley for the anniversary? A relatively cool 118.