November 2019 Summary – Cooler and Drier Than Average

Blue Hill Observatory November 2019 Summary:

November was very cool with much less rainfall than average. The 24-hour adjusted mean temperature for the month of 38.0 deg F was 4.1 degrees cooler than the 120-year average for November and 2.6 degrees cooler than the 1981-2010 30-year average. The month was the coldest November since 1996. The average maximum temperature of 46.0 deg F was 4.0 degrees below normal, and the average minimum temperature of 30.3 deg F was 3.2 degrees below normal. The warmest temperature for the month was 67F on the 1st, and the lowest temperature was 15F on the 13th. The high temperature on the 13th of 28F was a daily record low maximum temperature, surpassing 30F set in 1920, and it was also the third earliest maximum temperature colder than 30F on record, behind only 28F on November 8, 1894 and 29F on November 12th, 1894. Precipitation totaled 3.74 inches, which was about a half inch less than the long-term 120-year average and about one inch less than the 30-year mean. The greatest precipitation in 24 hours was 1.60 inches on the 24th. Snowfall totaled just 0.1 inches, which was about two inches less than the 30-year mean. There were two thunderstorm days during November, which brings the yearly total up to 17 or five fewer than average. The mean wind speed was 12.9 mph, and the prevailing wind direction for the month was from the west. A peak gust of 67 mph occurred from the south during the passage of a cold front on the 1st. November was sunnier than average with 144.2 hours of bright sunshine, or 51 percent of possible, which was 4 percent more than the long-term average.

Fall (September – November) 2019 Summary:

Fall 2019 was near average for temperature, rainfall and sunshine. The 24-hour adjusted mean temperature for Fall of 51.6 deg F was 0.6 degrees warmer than the 120-year average for September-November but 0.3 degrees cooler than the 1981-2010 30-year summer average. The season started warm, but ended with a cool November. Fall precipitation totaled 11.93 inches, what was one-third of an inch less than the 120-year long-term mean and about an inch and a half less than the 30-year normal. The greatest rainfall in 24 hours was 1.96 inches on October 16th-17th, and this storm set a new record low minimum sea-level pressure for October of 28.82 inches on the 17th. There were three thunderstorm days during Fall, which was exactly average. The average wind speed recorded during Fall was just 12.1 mph, which tied for the sixth lowest ever measured for the season. Sunshine was slightly below average during Fall with 52 percent of the possible bright sunshine, which was two percent less than the long-term mean of 54 percent.

Mike Iacono
Chief Scientist
Blue Hill Observatory