December 2022 Summary – Warmer and Wetter Than Average

Blue Hill Observatory December 2022 Summary: 

December was generally warm with more precipitation and less snowfall than expected. The approximated 24-hour mean temperature for the month of 34.1 deg F was 4.0 degree warmer than the 1891-2020 130-year average for December, and it was 1.3 degrees warmer than the 1991-2020 30-year average. The average maximum temperature of 41.7 deg F was 1.5 degrees warmer than the 30-year normal, and the average minimum temperature of 27.0 deg F was 2.1 degrees warmer than the 30-year normal. The temperature was variable during December, with several swings above and below average. The warmest day on the 30th saw a new daily record maximum of 63F, which surpassed the previous record of 60F set in 1984. The coldest temperature was 6F on the morning of the 24th, which followed heavy rain, strong winds, and a high temperature of 55F on the 23rd due to a major storm that brought snow, rain, severe weather and bitter cold across much of the country. The total precipitation was 5.91 inches, which was 0.52 inches more than the 30-year normal. The greatest rainfall in 24 hours was 2.16 inches on the 16th-17th during a rain event that brought a storm total of 2.42 inches over two days from the 15th-17th. Snowfall was just 2.7 inches, which was 9.9 inches less than normal for December. Most of this snow, 2.5 inches, fell on the 10th-11th. There were no thunderstorm days during the month, and the annual total of 18 was four below average. The mean wind speed was 14.1 mph, and the prevailing wind direction was from the west-southwest. The highest wind gust was 74 mph from the southeast on the 23rd in the warm air mass ahead of the Arctic cold front that rapidly dropped the temperature later than night. December sunshine was much above average with 147.0 hours of bright sunshine, or 54 percent of possible, which was eight percent more than the long-term average for the month.

Mike Iacono
Chief Scientist
Blue Hill Observatory