June 2024 Summary – Fourth Warmest on Record

Blue Hill Observatory June 2024 Summary: 

June temperature was much above average with near average rainfall and abundant sunshine. The approximated 24-hour mean temperature for the month of 68.4 deg F was 4.1 degrees warmer than the 1891-2020 130-year average for June, and it was 2.7 degrees warmer than the 1991-2020 30-year average. The month was the fourth warmest June on record. The average maximum temperature of 79.6 deg F was 4.2 degrees warmer than the 30-year normal, which was also the fourth warmest on record. The average minimum temperature of 58.5 deg F was 0.9 degrees warmer than the 30-year normal. The warmest temperature reached 94F on the 20th, which tied the record for the date set in 1953. This reading was the last day of a three-day heat wave on the 18th-20th, which was only the fourteenth heatwave in June on record at the Observatory. The high temperature of 93F on the 19th surpassed the previous record for the date of 92F set in 1923. The lowest temperature was 51F on the 16th. June mean water vapor pressure, which is an absolute measure of water vapor in the air, was 17.3 mb, which corresponds to a mean dew point of about 59F. This amount was well above the long-term mean water vapor pressure for June of 15.4 mb, which equals a mean dew point of about 56F. The total precipitation was 4.86 inches, which was just 0.23 inches more than the 30-year normal. The greatest amount in 24 hours was 1.83 inches on the 26th-27th, during several periods of thunderstorms and downpours. The calendar day rainfall of 1.63 inches on the 26th surpassed the previous record for the date of 1.22 inches set in 1938. There were five thunderstorm days during June, which was one more than average, and the total for the year through June was ten. The mean wind speed was 10.7 mph, and the prevailing wind direction was from the south-southwest. The highest wind gust was 50 mph from the northwest during a mid-day thunderstorm on the 14th. June sunshine was much above average with 281.1 hours of bright sunshine, or 64 percent of possible, which was nine percent more than the long-term average for the month.

BHO Warmest June Approximated 24-Hour Mean Temperature, deg F (1885-2024):

1) 70.0 in 2021
2) 68.7 in 1999
3) 68.5 in 2001
4) 68.4 in 2024
5) 68.3 in 1925
   68.3 in 1930
7) 68.2 in 1994
8) 68.0 in 1943

BHO Warmest June Average Maximum Temperature, deg F (1885-2024):

1) 80.9 in 2021
2) 80.4 in 1930
3) 80.3 in 1949
4) 79.6 in 2024
5) 79.5 in 1957
   79.5 in 1976
7) 79.3 in 1943
   79.3 in 1999

BHO Longest June Heatwaves, days (1885-2024):

1) 4, 3-6 June 1925 (93/94/91/95)
   4, 7-10 June 2008 (91/91/94/98)
3) 3, 3-5 June 1919 (98/99/92)
   3, 19-21 June 1923 (92/91/90)
   3, 13-15 June 1956 (92/93/92)
   3, 8-10 June 1984 (94/92/92)
   3, 13-15 June 1988 (93/92/94)
   3, 27-29 June 1991 (91/95/91)
   3, 17-19 June 1994 (91/93/90)
   3, 26-28 June 1999 (90/93/91)
   3, 20-22 June 2012 (93/94/93)
   3, 6-8 June 2021 (91/92/92)
   3, 28-30 June 2021 (93/95/94)
   3, 18-20 June 2024 (92/93/94)

Mike Iacono
Chief Scientist
Blue Hill Observatory