June 2019 Summary – Close to Average

Blue Hill Observatory

June 2019 Summary:

June was generally close to average for temperature, rainfall and sunshine. The 24-hour adjusted mean temperature for the month of 66.0 deg F was 1.9 degrees warmer than the 120-year average for June and 0.7 degrees warmer than the 1981-2010 30-year average. The average maximum temperature of 75.1 deg F was just 0.1 degrees above normal, and the average minimum temperature of 57.3 deg F was just 0.2 degrees above normal. The highest temperature for the month was 88F on the 28th, and the lowest temperature was 45F on the 4th. Precipitation totaled 4.08 inches, which was nearly a half inch more than the long-term 120-year average and a quarter inch less than the 30-year mean. The greatest rainfall in 24 hours was 1.30 inches on the 10th-11th. There were three thunderstorm days during June on the 22nd, 29th, and 30th, which brings the yearly total up to eight thunderstorm days through June, or one less than average. The thunderstorms on the 29th brought heavy downpours to the area shortly after sunrise. After a cloudy and cool spring, the first ripe blueberries of the season were not observed until June 28th, which was seven days later than the long term average date of June 21st. This was the latest date on which the first ripe blueberries were observed within the instrument enclosure on the summit since June 29th, 1982. The mean wind speed was 10.5 mph, which was the third lowest on record for June, and the prevailing direction was from the south. A peak gust of 41 mph from the west occurred on the 3rd. June sunshine was close to average with 235.3 hours, or 54 percent of the possible bright sunshine, which was one percent less than the long-term average.

BHO Lowest June Mean Wind Speed, mph (1885-2019):

1) 9.8 in 2009
2) 10.3 in 1895
3) 10.5 in 2019
4) 10.6 in 2005
   10.6 in 2008
   10.6 in 2011
   10.6 in 2014

Mike Iacono
Chief Scientist
Blue Hill Observatory