January 2021 Summary – Warmer and Drier than Average

Blue Hill Observatory January 2021 Summary:

January was generally warmer, drier and less snowy than average. The 24-hour adjusted mean temperature for the month of 28.8 deg F was 2.9 degrees warmer than the 1891-2020 130-year average for January, and it was 2.6 degrees warmer than the 1981-2010 30-year average. The average maximum temperature of 35.4 deg F was 1.6 degrees warmer than the 30-year mean, and the average minimum temperature of 22.5 deg F was 5.4 degrees warmer than the 30-year mean. The highest temperature observed all month was 52F on the 16th, and the lowest temperature was 2F on the 31st. Overall, the month was warm until very cold weather arrived during the last few days of the month. January precipitation was 2.32 inches, which was about two inches less than the long-term 130-year average and the 1981-2010 30-year mean. Most of this precipitation, 1.36 inches, fell as rain on the 16th, which was also the greatest amount in 24 hours. A thunderstorm was also observed on the 16th. Snowfall for the month was 7.2 inches, which was ten inches less than the long-term mean for January. Most of that snow, 4.2 inches, fell in a single snowfall on the 26th-27th, which was also the greatest amount in 24 hours. The mean wind speed for the month was 11.7 mph, which was the lowest on record for January, and the prevailing wind direction was from the northwest. The monthly peak wind gust was 48 mph from the east-southeast during the rain storm on the 16th. January sunshine was close to average with 134.2 hours of bright sunshine, or 47 percent of possible, which was one percent more than the long-term average.

BHO Lowest January Mean Wind Speed, mph (1886-2021):

1) 11.7 in 2021
2) 12.2 in 2001
3) 12.8 in 2011
   12.8 in 2020
5) 13.1 in 2009


Mike Iacono
Chief Scientist
Blue Hill Observatory