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2012 a Record Warm Year for Continental U.S.

By: Christopher C. Burt, 8:36 PM GMT on January 02, 2013

2012 a Record Warm Year for Continental U.S.

As most of you probably already know, 2012 has been the warmest calendar year on record for the continental U.S. according to NCDC data going back to 1895. The final actual average temperature for the year has yet to be tallied but as of Dec. 1st stood at 57.06°F (13.92°C), well above the previous record for the same time period (first 11 months of the year) of 56.05°F (13.36°C) set in 1934. What was truly astonishing, however, was the ratio of heat records versus cold records that was established over the course of the year.

Below is a chart of the total number of NCDC sites that measured daily and/or monthly record high and low temperatures. There are about 5,500 of these sites in the NCDC database all together and it is important to note that the first two columns of this table are not all-time record highs or all-time record lows but daily and monthly records. So, for instance, a single site may have broken dozens of daily records over the course of the year. The 5th and 6th columns are for all-time record highs and lows: a total of 362 such heat records and 0 such cold records occurred. The ratio of daily record highs to daily record lows (about 5 to 1) were the greatest for any year in NCDC records:

Below are two charts showing the ratio 1:1 of number of daily record highs versus daily record lows (top chart) and monthly record highs versus monthly record lows (bottom chart) for each decade since the 1920s. Note that we are only looking at two years so far this decade:

These charts were produced by Guy Walton of the Weather Channel.

The Weather Underground climate extremes database follows 298 significant city sites in the U.S. which represent all climate divisions and major population centers. More importantly, they all have long periods of record (POR’s) dating back to the 19th century in most cases.

This past summer some 22 of these 298 sites beat or tied their all-time absolute maximum temperature on record. This was the most since the infamous summer of 1936. No site recorded their coldest such.

The following cities from the WU database recorded their all-time single hottest month on record (no sites recorded their coldest month on record):

The last year that one of the 298 WU sites reported an all-time record cold month was 1994 when Caribou, Maine and Bayfield, Wisconsin recorded such. The last all-time absolute minimum temperature record for a specific WU site was on February 3, 2011 when Santa Fe, New Mexico fell to -18°F (-27.8°C). It was during that cold wave, you may recall, that Oklahoma set a new cold state record with a -31° (-35°C) reading at Nowata on February 10th.

Christopher C. Burt
Weather Historian

Extreme Weather Temperature

The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.