Tucson all-time low temperature

This January 7, 2023 marks the 110 year anniversary of the coldest low temperature recorded in Tucson. On the morning of January 7, 1913, the mercury bottomed out at a frigid 6° at the University of Arizona, then the official temperature location in Tucson. Based on newspaper reports some low-lying areas in Tucson did report temperatures as low as zero. The 6° broke the previous record low of 10° which occurred on December 14, 1901.

The high on the 6th of 36° set a new all-time record low maximum temperature, breaking the previous record of 37° from February 6, 1899 & January 5, 1910. This record still stands today but has been tied three times (January 21, 1937; January 3, 1949 & January 4, 1949). In recent times, the closest Tucson has come to this record was during the February 2011 cold snap (38 on the 3rd, which currently stands as the 7th coldest high temperature on record).

This record setting cold in Tucson and other parts of Arizona was associated with an Arctic cold snap that also hit southern California. Newspapers reported that the cold wave in southern California was historic at the time and brought an estimated $20,000,000 to $40,000,000 worth of damage to the citrus crop. Damage also occurred to the citrus crop in Arizona with the money loss being significantly less.

The following account was taken from the Monthly Weather Review for January 1913. This review was published by the American Meteorological Society.

"The conditions that led up to the severe weather may be briefly stated as having their start in a low-pressure area on the morning of the 4th, extending from Arkansas on the east to the lower Colorado River. In this region the pressure was more than half an inch below the normal, while in the distant Northwest there was an excess of four-tenths of an inch, but unaccompanied by unusually low temperatures. During the next 24 hours there was a movement of the anticyclone southward on the east side of the Continental Divide, blocking any further progress eastward of the western depression then central in southwestern Colorado, and at the same time forcing the eastern part of the depression southward to the west coast of the Gulf of Mexico. During the slow progress of filling up the depression west of the Continental Divide, extremely cold weather developed, and temperatures as low as or lower than any previously observed occurred in many locals."

Remember that weather forecasting was much different 110 years ago. For a better idea on how much has changed in observing the weather, NOAA has a webpage title "A History of Observing the Weather". 

The following two tables shows the 10 coldest low temperatures that have occurred in Tucson during two selected time periods.