-69.6ºC is the new magic number, but it was actually recorded in 1991. At the end of September of this year, the World Meteorological Organization recognized this measurement from an automated weather station in Greenland as the new coldest temperature ever recorded in the northern hemisphere. That's -93.3ºF!
The World Meteorological Organization didn't start recording these extreme data points (like record highs and lows) until 2007. In the last several years, climate historians have been working through old data to establish the Archive of Weather and Climate Extremes. In looking back through the numbers, the "climate detectives" as the WMO calls them, discovered this potential new record. They then had to evaluate the equipment that measured this temperature and the team of scientists supervising the equipment. "The automatic weather station operated for two years in the early 1990s as part of a network established by the University of Wisconsin-Madison to record the meteorological conditions around the Greenland Crest during the Greenland Ice Sheet Project. In 1994 it was returned to the laboratory for testing and then sent for use in the Antarctic."
It's important to put current data in context of records, but it's also important to look back through as much data as we can gather to ensure those records are complete. With so much discussion about climate change, this kind of analysis is how you can be sure you are getting more accurate picture of our changing global climate.
The previous record low temperature in the northern hemisphere was -67.8°C recorded at the Russian sites of Verkhoyanksk in February 1892 and Oimekon in January 1933. The world’s lowest temperature on record is -89.2°C (-128.6°F). That was measured at a high-altitude weather station in Antarctica in July 1983.
