June 2017 Summary – Warmer and Wetter than Average

Blue Hill Observatory

June 2017 Summary:

June was generally warm with more rainfall than average. The 24-hour mean temperature for the month of 67.0 deg F was 2.9 degrees warmer than the 120-year average for June and nearly two degrees warmer than the 1981-2010 30-year average. The high temperature of 94F on the 12th was a daily record that surpassed a reading of 92F set on that date in 1973. The coldest temperature during June was 45F on the 6th. The final heating degree day total for the 2016-2017 heating season was 5725, which was 651 less than the 30-year normal. A total of 6.03 inches of precipitation was observed during June, which was two and a third inches more than the long-term 120-year average and an inch and three-quarters more than the 30-year mean. The greatest amount in 24 hours was 2.19 inches on the 5th-6th during a period of rain that brought almost three inches of precipitation, almost half the monthly total, from the 4th to the 7th and a high temperature of only 49F on the 6th. There were three thunderstorm days during June on the 9th, 23rd and 27th. The first ripe blueberry of the season was observed in the instrument enclosure on the summit on the 20th. This date was one day earlier than the long-term average of June 21 and 13 days later than the date of last year’s first ripe blueberry. The mean wind speed for June was 12.1 mph, and the prevailing direction was from the west. The peak gust was 48 mph from the north from the distant thunderstorm on the 9th. June bright sunshine was above average with 250.5 hours or 57 percent of possible, which was two percent more than the long-term mean.

Mike Iacono
Chief Scientist
Blue Hill Observatory